Option "-ddump-rn-ast" dumps imports and exports too
[ghc.git] / aclocal.m4
index 2aa55d7..d053311 100644 (file)
@@ -14,19 +14,14 @@ AC_DEFUN([GHC_SELECT_FILE_EXTENSIONS],
         AC_MSG_WARN([I'm assuming you wanted to build for i386-unknown-mingw32])
         exit 1
         ;;
         AC_MSG_WARN([I'm assuming you wanted to build for i386-unknown-mingw32])
         exit 1
         ;;
-    *-unknown-mingw32)
+    # examples: i386-unknown-mingw32, i686-w64-mingw32, x86_64-w64-mingw32
+    *-mingw32)
         windows=YES
         $2='.exe'
         $3='.dll'
         ;;
         windows=YES
         $2='.exe'
         $3='.dll'
         ;;
-    i386-apple-darwin|powerpc-apple-darwin)
-        $3='.dylib'
-        ;;
-    x86_64-apple-darwin)
-        $3='.dylib'
-        ;;
-    arm-apple-darwin10|i386-apple-darwin11|aarch64-apple-darwin14)
-        $2='.a'
+    # apple platform uses .dylib (macOS, iOS, ...)
+    *-apple-*)
         $3='.dylib'
         ;;
     esac
         $3='.dylib'
         ;;
     esac
@@ -141,9 +136,13 @@ AC_DEFUN([FPTOOLS_SET_PLATFORM_VARS],
     TargetVendor_CPP=`  echo "$TargetVendor"   | sed -e 's/\./_/g' -e 's/-/_/g'`
     TargetOS_CPP=`      echo "$TargetOS"       | sed -e 's/\./_/g' -e 's/-/_/g'`
 
     TargetVendor_CPP=`  echo "$TargetVendor"   | sed -e 's/\./_/g' -e 's/-/_/g'`
     TargetOS_CPP=`      echo "$TargetOS"       | sed -e 's/\./_/g' -e 's/-/_/g'`
 
+    # we intend to pass trough --targets to llvm as is.
+    LLVMTarget_CPP=`    echo "$target"`
+
     echo "GHC build  : $BuildPlatform"
     echo "GHC host   : $HostPlatform"
     echo "GHC target : $TargetPlatform"
     echo "GHC build  : $BuildPlatform"
     echo "GHC host   : $HostPlatform"
     echo "GHC target : $TargetPlatform"
+    echo "LLVM target: $target"
 
     AC_SUBST(BuildPlatform)
     AC_SUBST(HostPlatform)
 
     AC_SUBST(BuildPlatform)
     AC_SUBST(HostPlatform)
@@ -159,6 +158,7 @@ AC_DEFUN([FPTOOLS_SET_PLATFORM_VARS],
     AC_SUBST(HostOS_CPP)
     AC_SUBST(BuildOS_CPP)
     AC_SUBST(TargetOS_CPP)
     AC_SUBST(HostOS_CPP)
     AC_SUBST(BuildOS_CPP)
     AC_SUBST(TargetOS_CPP)
+    AC_SUBST(LLVMTarget_CPP)
 
     AC_SUBST(HostVendor_CPP)
     AC_SUBST(BuildVendor_CPP)
 
     AC_SUBST(HostVendor_CPP)
     AC_SUBST(BuildVendor_CPP)
@@ -188,11 +188,17 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
             test -z "[$]2" || eval "[$]2=ArchPPC"
             ;;
         powerpc64)
             test -z "[$]2" || eval "[$]2=ArchPPC"
             ;;
         powerpc64)
-            test -z "[$]2" || eval "[$]2=ArchPPC_64"
+            test -z "[$]2" || eval "[$]2=\"ArchPPC_64 {ppc_64ABI = ELF_V1}\""
+            ;;
+        powerpc64le)
+            test -z "[$]2" || eval "[$]2=\"ArchPPC_64 {ppc_64ABI = ELF_V2}\""
             ;;
         sparc)
             test -z "[$]2" || eval "[$]2=ArchSPARC"
             ;;
             ;;
         sparc)
             test -z "[$]2" || eval "[$]2=ArchSPARC"
             ;;
+        sparc64)
+            test -z "[$]2" || eval "[$]2=ArchSPARC64"
+            ;;
         arm)
             GET_ARM_ISA()
             test -z "[$]2" || eval "[$]2=\"ArchARM {armISA = \$ARM_ISA, armISAExt = \$ARM_ISA_EXT, armABI = \$ARM_ABI}\""
         arm)
             GET_ARM_ISA()
             test -z "[$]2" || eval "[$]2=\"ArchARM {armISA = \$ARM_ISA, armISAExt = \$ARM_ISA_EXT, armABI = \$ARM_ABI}\""
@@ -209,7 +215,7 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
         mipsel)
             test -z "[$]2" || eval "[$]2=ArchMipsel"
             ;;
         mipsel)
             test -z "[$]2" || eval "[$]2=ArchMipsel"
             ;;
-        hppa|hppa1_1|ia64|m68k|powerpc64le|rs6000|s390|s390x|sparc64|vax)
+        hppa|hppa1_1|ia64|m68k|rs6000|s390|s390x|sh4|vax)
             test -z "[$]2" || eval "[$]2=ArchUnknown"
             ;;
         *)
             test -z "[$]2" || eval "[$]2=ArchUnknown"
             ;;
         *)
@@ -221,24 +227,20 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
 
     checkVendor() {
         case [$]1 in
 
     checkVendor() {
         case [$]1 in
-        dec|unknown|hp|apple|next|sun|sgi|ibm|montavista|portbld)
+        dec|none|unknown|hp|apple|next|sun|sgi|ibm|montavista|portbld)
             ;;
         *)
             ;;
         *)
-            echo "Unknown vendor [$]1"
-            exit 1
+            AC_MSG_WARN([Unknown vendor [$]1])
             ;;
         esac
     }
 
     checkOS() {
         case [$]1 in
             ;;
         esac
     }
 
     checkOS() {
         case [$]1 in
-        linux)
+        linux|linux-android)
             test -z "[$]2" || eval "[$]2=OSLinux"
             ;;
             test -z "[$]2" || eval "[$]2=OSLinux"
             ;;
-        ios)
-            test -z "[$]2" || eval "[$]2=OSiOS"
-            ;;
-        darwin)
+        darwin|ios)
             test -z "[$]2" || eval "[$]2=OSDarwin"
             ;;
         solaris2)
             test -z "[$]2" || eval "[$]2=OSDarwin"
             ;;
         solaris2)
@@ -265,17 +267,14 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
         haiku)
             test -z "[$]2" || eval "[$]2=OSHaiku"
             ;;
         haiku)
             test -z "[$]2" || eval "[$]2=OSHaiku"
             ;;
-        osf3)
-            test -z "[$]2" || eval "[$]2=OSOsf3"
-            ;;
         nto-qnx)
             test -z "[$]2" || eval "[$]2=OSQNXNTO"
             ;;
         nto-qnx)
             test -z "[$]2" || eval "[$]2=OSQNXNTO"
             ;;
-        dragonfly|osf1|hpux|linuxaout|freebsd2|cygwin32|gnu|nextstep2|nextstep3|sunos4|ultrix|irix|aix)
+        dragonfly|hpux|linuxaout|freebsd2|gnu|nextstep2|nextstep3|sunos4|ultrix)
             test -z "[$]2" || eval "[$]2=OSUnknown"
             ;;
             test -z "[$]2" || eval "[$]2=OSUnknown"
             ;;
-        linux-android)
-            test -z "[$]2" || eval "[$]2=OSAndroid"
+        aix)
+            test -z "[$]2" || eval "[$]2=OSAIX"
             ;;
         *)
             echo "Unknown OS '[$]1'"
             ;;
         *)
             echo "Unknown OS '[$]1'"
@@ -316,9 +315,18 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
     dnl so we empty CFLAGS while running this test
     CFLAGS2="$CFLAGS"
     CFLAGS=
     dnl so we empty CFLAGS while running this test
     CFLAGS2="$CFLAGS"
     CFLAGS=
+    case $TargetArch in
+      arm)
+        dnl See #13937.
+        progbits="%progbits"
+        ;;
+      *)
+        progbits="@progbits"
+        ;;
+    esac
     AC_MSG_CHECKING(for GNU non-executable stack support)
     AC_COMPILE_IFELSE(
     AC_MSG_CHECKING(for GNU non-executable stack support)
     AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM([__asm__ (".section .note.GNU-stack,\"\",@progbits");], [0])],
+        [AC_LANG_PROGRAM([__asm__ (".section .note.GNU-stack,\"\",$progbits");], [0])],
         [AC_MSG_RESULT(yes)
          HaskellHaveGnuNonexecStack=True],
         [AC_MSG_RESULT(no)
         [AC_MSG_RESULT(yes)
          HaskellHaveGnuNonexecStack=True],
         [AC_MSG_RESULT(no)
@@ -383,6 +391,8 @@ AC_DEFUN([GET_ARM_ISA],
                          defined(__ARM_ARCH_6T2__) || \
                          defined(__ARM_ARCH_6Z__)  || \
                          defined(__ARM_ARCH_6ZK__) || \
                          defined(__ARM_ARCH_6T2__) || \
                          defined(__ARM_ARCH_6Z__)  || \
                          defined(__ARM_ARCH_6ZK__) || \
+                         defined(__ARM_ARCH_6K__)  || \
+                         defined(__ARM_ARCH_6KZ__) || \
                          defined(__ARM_ARCH_6M__)
                          return 0;
                      #else
                          defined(__ARM_ARCH_6M__)
                          return 0;
                      #else
@@ -442,6 +452,8 @@ AC_DEFUN([GET_ARM_ISA],
                     [ARM_ABI="SOFTFP"]
                )]
         )
                     [ARM_ABI="SOFTFP"]
                )]
         )
+
+        AC_SUBST(ARM_ISA)
 ])
 
 
 ])
 
 
@@ -450,7 +462,7 @@ AC_DEFUN([GET_ARM_ISA],
 # Set the variables used in the settings file
 AC_DEFUN([FP_SETTINGS],
 [
 # Set the variables used in the settings file
 AC_DEFUN([FP_SETTINGS],
 [
-    if test "$windows" = YES
+    if test "$windows" = YES -a "$EnableDistroToolchain" = "NO"
     then
         mingw_bin_prefix=mingw/bin/
         SettingsCCompilerCommand="\$topdir/../${mingw_bin_prefix}gcc.exe"
     then
         mingw_bin_prefix=mingw/bin/
         SettingsCCompilerCommand="\$topdir/../${mingw_bin_prefix}gcc.exe"
@@ -458,21 +470,56 @@ AC_DEFUN([FP_SETTINGS],
         SettingsHaskellCPPFlags="$HaskellCPPArgs"
         SettingsLdCommand="\$topdir/../${mingw_bin_prefix}ld.exe"
         SettingsArCommand="\$topdir/../${mingw_bin_prefix}ar.exe"
         SettingsHaskellCPPFlags="$HaskellCPPArgs"
         SettingsLdCommand="\$topdir/../${mingw_bin_prefix}ld.exe"
         SettingsArCommand="\$topdir/../${mingw_bin_prefix}ar.exe"
+        SettingsRanlibCommand="\$topdir/../${mingw_bin_prefix}ranlib.exe"
         SettingsPerlCommand='$topdir/../perl/perl.exe'
         SettingsDllWrapCommand="\$topdir/../${mingw_bin_prefix}dllwrap.exe"
         SettingsWindresCommand="\$topdir/../${mingw_bin_prefix}windres.exe"
         SettingsPerlCommand='$topdir/../perl/perl.exe'
         SettingsDllWrapCommand="\$topdir/../${mingw_bin_prefix}dllwrap.exe"
         SettingsWindresCommand="\$topdir/../${mingw_bin_prefix}windres.exe"
-        SettingsTouchCommand='$topdir/touchy.exe'
+        SettingsTouchCommand='$topdir/bin/touchy.exe'
+    elif test "$EnableDistroToolchain" = "YES"
+    then
+        SettingsCCompilerCommand="$(basename $CC)"
+        SettingsCCompilerFlags="$CONF_CC_OPTS_STAGE2"
+        SettingsHaskellCPPCommand="$(basename $HaskellCPPCmd)"
+        SettingsHaskellCPPFlags="$HaskellCPPArgs"
+        SettingsLdCommand="$(basename $LdCmd)"
+        SettingsArCommand="$(basename $ArCmd)"
+        SettingsPerlCommand="$(basename $PerlCmd)"
+        SettingsDllWrapCommand="$(basename $DllWrapCmd)"
+        SettingsWindresCommand="$(basename $WindresCmd)"
+        SettingsTouchCommand='$topdir/bin/touchy.exe'
     else
     else
-        SettingsCCompilerCommand="$WhatGccIsCalled"
+        SettingsCCompilerCommand="$CC"
         SettingsHaskellCPPCommand="$HaskellCPPCmd"
         SettingsHaskellCPPFlags="$HaskellCPPArgs"
         SettingsLdCommand="$LdCmd"
         SettingsArCommand="$ArCmd"
         SettingsHaskellCPPCommand="$HaskellCPPCmd"
         SettingsHaskellCPPFlags="$HaskellCPPArgs"
         SettingsLdCommand="$LdCmd"
         SettingsArCommand="$ArCmd"
+        SettingsRanlibCommand="$RanlibCmd"
         SettingsPerlCommand="$PerlCmd"
         SettingsPerlCommand="$PerlCmd"
-        SettingsDllWrapCommand="/bin/false"
-        SettingsWindresCommand="/bin/false"
-        SettingsLibtoolCommand="libtool"
-        SettingsTouchCommand='touch'
+        if test -z "$DllWrapCmd"
+        then
+            SettingsDllWrapCommand="/bin/false"
+        else
+            SettingsDllWrapCommand="$DllWrapCmd"
+        fi
+        if test -z "$WindresCmd"
+        then
+            SettingsWindresCommand="/bin/false"
+        else
+            SettingsWindresCommand="$WindresCmd"
+        fi
+       SettingsTouchCommand='touch'
+    fi
+    if test -z "$LibtoolCmd"
+    then
+      SettingsLibtoolCommand="libtool"
+    else
+      SettingsLibtoolCommand="$LibtoolCmd"
+    fi
+    if test -z "$ClangCmd"
+    then
+        SettingsClangCommand="clang"
+    else
+        SettingsClangCommand="$ClangCmd"
     fi
     if test -z "$LlcCmd"
     then
     fi
     if test -z "$LlcCmd"
     then
@@ -488,28 +535,74 @@ AC_DEFUN([FP_SETTINGS],
     fi
     SettingsCCompilerFlags="$CONF_CC_OPTS_STAGE2"
     SettingsCCompilerLinkFlags="$CONF_GCC_LINKER_OPTS_STAGE2"
     fi
     SettingsCCompilerFlags="$CONF_CC_OPTS_STAGE2"
     SettingsCCompilerLinkFlags="$CONF_GCC_LINKER_OPTS_STAGE2"
+    SettingsCCompilerSupportsNoPie="$CONF_GCC_SUPPORTS_NO_PIE"
     SettingsLdFlags="$CONF_LD_LINKER_OPTS_STAGE2"
     AC_SUBST(SettingsCCompilerCommand)
     AC_SUBST(SettingsHaskellCPPCommand)
     AC_SUBST(SettingsHaskellCPPFlags)
     AC_SUBST(SettingsCCompilerFlags)
     AC_SUBST(SettingsCCompilerLinkFlags)
     SettingsLdFlags="$CONF_LD_LINKER_OPTS_STAGE2"
     AC_SUBST(SettingsCCompilerCommand)
     AC_SUBST(SettingsHaskellCPPCommand)
     AC_SUBST(SettingsHaskellCPPFlags)
     AC_SUBST(SettingsCCompilerFlags)
     AC_SUBST(SettingsCCompilerLinkFlags)
+    AC_SUBST(SettingsCCompilerSupportsNoPie)
     AC_SUBST(SettingsLdCommand)
     AC_SUBST(SettingsLdFlags)
     AC_SUBST(SettingsArCommand)
     AC_SUBST(SettingsLdCommand)
     AC_SUBST(SettingsLdFlags)
     AC_SUBST(SettingsArCommand)
+    AC_SUBST(SettingsRanlibCommand)
     AC_SUBST(SettingsPerlCommand)
     AC_SUBST(SettingsDllWrapCommand)
     AC_SUBST(SettingsWindresCommand)
     AC_SUBST(SettingsLibtoolCommand)
     AC_SUBST(SettingsTouchCommand)
     AC_SUBST(SettingsPerlCommand)
     AC_SUBST(SettingsDllWrapCommand)
     AC_SUBST(SettingsWindresCommand)
     AC_SUBST(SettingsLibtoolCommand)
     AC_SUBST(SettingsTouchCommand)
+    AC_SUBST(SettingsClangCommand)
     AC_SUBST(SettingsLlcCommand)
     AC_SUBST(SettingsOptCommand)
 ])
 
     AC_SUBST(SettingsLlcCommand)
     AC_SUBST(SettingsOptCommand)
 ])
 
+# Helper for cloning a shell variable's state
+AC_DEFUN([FP_COPY_SHELLVAR],
+[if test -n "${$1+set}"; then $2="$$1"; else unset $2; fi ])
+
+# FP_SET_CFLAGS_C99
+# ----------------------------------
+# figure out which CFLAGS are needed to place the compiler into C99 mode
+# $1 is name of CC variable (unmodified)
+# $2 is name of CC flags variable (augmented if needed)
+# $3 is name of CPP flags variable (augmented if needed)
+AC_DEFUN([FP_SET_CFLAGS_C99],
+[
+    dnl save current state of AC_PROG_CC_C99
+    FP_COPY_SHELLVAR([CC],[fp_save_CC])
+    FP_COPY_SHELLVAR([CFLAGS],[fp_save_CFLAGS])
+    FP_COPY_SHELLVAR([CPPFLAGS],[fp_save_CPPFLAGS])
+    FP_COPY_SHELLVAR([ac_cv_prog_cc_c99],[fp_save_cc_c99])
+    dnl set local state
+    CC="$$1"
+    CFLAGS="$$2"
+    CPPFLAGS="$$3"
+    unset ac_cv_prog_cc_c99
+    dnl perform detection
+    _AC_PROG_CC_C99
+    fp_cc_c99="$ac_cv_prog_cc_c99"
+    case "x$ac_cv_prog_cc_c99" in
+      x)   ;; # noop
+      xno) AC_MSG_ERROR([C99-compatible compiler needed]) ;;
+      *)   $2="$$2 $ac_cv_prog_cc_c99"
+           $3="$$3 $ac_cv_prog_cc_c99"
+           ;;
+    esac
+    dnl restore saved state
+    FP_COPY_SHELLVAR([fp_save_CC],[CC])
+    FP_COPY_SHELLVAR([fp_save_CFLAGS],[CFLAGS])
+    FP_COPY_SHELLVAR([fp_save_CPPFLAGS],[CPPFLAGS])
+    FP_COPY_SHELLVAR([fp_save_cc_c99],[ac_cv_prog_cc_c99])
+    dnl cleanup
+    unset fp_save_CC
+    unset fp_save_CFLAGS
+    unset fp_save_cc_c99
+])
 
 # FPTOOLS_SET_C_LD_FLAGS
 # ----------------------------------
 
 # FPTOOLS_SET_C_LD_FLAGS
 # ----------------------------------
-# Set the C, LD and CPP flags for a given platform
+# Set the C, LD and CPP flags for a given platform.
 # $1 is the platform
 # $2 is the name of the CC flags variable
 # $3 is the name of the linker flags variable when linking with gcc
 # $1 is the platform
 # $2 is the name of the CC flags variable
 # $3 is the name of the linker flags variable when linking with gcc
@@ -532,18 +625,6 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
     i386-portbld-freebsd*)
         $2="$$2 -march=i686"
         ;;
     i386-portbld-freebsd*)
         $2="$$2 -march=i686"
         ;;
-    i386-apple-darwin)
-        $2="$$2 -m32"
-        $3="$$3 -m32"
-        $4="$$4 -arch i386"
-        $5="$$5 -m32"
-        ;;
-    x86_64-apple-darwin)
-        $2="$$2 -m64"
-        $3="$$3 -m64"
-        $4="$$4 -arch x86_64"
-        $5="$$5 -m64"
-        ;;
     x86_64-unknown-solaris2)
         $2="$$2 -m64"
         $3="$$3 -m64"
     x86_64-unknown-solaris2)
         $2="$$2 -m64"
         $3="$$3 -m64"
@@ -565,6 +646,34 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
         $3="$$3 -D_HPUX_SOURCE"
         $5="$$5 -D_HPUX_SOURCE"
         ;;
         $3="$$3 -D_HPUX_SOURCE"
         $5="$$5 -D_HPUX_SOURCE"
         ;;
+    arm*linux*)
+        # On arm/linux and arm/android, tell gcc to generate Arm
+        # instructions (ie not Thumb).
+        $2="$$2 -marm"
+        $3="$$3 -Wl,-z,noexecstack"
+        $4="$$4 -z noexecstack"
+        ;;
+
+    aarch64*linux*)
+        $3="$$3 -Wl,-z,noexecstack"
+        $4="$$4 -z noexecstack"
+        ;;
+
+    powerpc-ibm-aix*)
+        # We need `-D_THREAD_SAFE` to unlock the thread-local `errno`.
+        $2="$$2 -D_THREAD_SAFE"
+        $3="$$3 -D_THREAD_SAFE -Wl,-bnotextro"
+        $4="$$4 -bnotextro"
+        $5="$$5 -D_THREAD_SAFE"
+        ;;
+
+    x86_64-*-openbsd*)
+        # We need -z wxneeded at least to link ghc-stage2 to workaround
+        # W^X issue in GHCi on OpenBSD current (as of Aug 2016)
+        $3="$$3 -Wl,-z,wxneeded"
+        $4="$$4 -z wxneeded"
+        ;;
+
     esac
 
     # If gcc knows about the stack protector, turn it off.
     esac
 
     # If gcc knows about the stack protector, turn it off.
@@ -580,21 +689,6 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
 ])
 
 
 ])
 
 
-AC_DEFUN([FP_PATH_PROG],[
-    AC_PATH_PROG($1,$2,$3,$4,$5,$6)
-    # If we have a cygwin path for something, and we try to run it
-    # from cabal or python, then it'll fail. So we convert to a
-    # native path.
-    if test "$HostOS"     = "mingw32" && \
-       test "${OSTYPE}"  != "msys"    && \
-       test "${$1}" != ""
-    then
-        # Canonicalise to <drive>:/path/to/gcc
-        $1=`cygpath -m "${$1}"`
-    fi
-])
-
-
 # FP_VISIBILITY_HIDDEN
 # ----------------------------------
 # Is the visibility hidden attribute supported?
 # FP_VISIBILITY_HIDDEN
 # ----------------------------------
 # Is the visibility hidden attribute supported?
@@ -640,75 +734,6 @@ AC_DEFUN([FPTOOLS_FLOAT_WORD_ORDER_BIGENDIAN],
 ])
 
 
 ])
 
 
-# FP_ARG_WITH_PATH_GNU_PROG_GENERAL
-# --------------------
-# Find the specified command on the path or allow a user to set it manually
-# with a --with-<command> option.
-#
-# This is ignored on the mingw32 platform.
-#
-# $1 = the variable to set
-# $2 = the with option name
-# $3 = the command to look for
-# $4 = prepend target to program name? if 'no', use the name unchanged
-# $5 = optional? if 'no', then raise an error if the command isn't found
-#
-AC_DEFUN([FP_ARG_WITH_PATH_GNU_PROG_GENERAL],
-[
-AC_ARG_WITH($2,
-[AC_HELP_STRING([--with-$2=ARG],
-        [Use ARG as the path to $2 [default=autodetect]])],
-[
-    if test "$HostOS" = "mingw32"
-    then
-        AC_MSG_WARN([Request to use $withval will be ignored])
-    else
-        $1=$withval
-    fi
-
-    # Remember that we set this manually.  Used to override CC_STAGE0
-    # and friends later, if we are not cross-compiling.
-    With_$2=$withval
-],
-[
-    if test "$HostOS" != "mingw32"
-    then
-        if test "$4" = "no" -o "$target_alias" = "" ; then
-            AC_PATH_PROG([$1], [$3])
-        else
-            AC_PATH_PROG([$1], [$target_alias-$3])
-        fi
-        if test "$5" = "no" -a -z "$$1"
-        then
-            AC_MSG_ERROR([cannot find $3 in your PATH])
-        fi
-    fi
-]
-)
-]) # FP_ARG_WITH_PATH_GNU_PROG_GENERAL
-
-
-# FP_ARG_WITH_PATH_GNU_PROG
-# --------------------
-# The usual case: prepend the target, and the program is not optional.
-AC_DEFUN([FP_ARG_WITH_PATH_GNU_PROG],
-[FP_ARG_WITH_PATH_GNU_PROG_GENERAL([$1], [$2], [$3], [yes], [no])])
-
-# FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL
-# --------------------
-# Same as FP_ARG_WITH_PATH_GNU_PROG but no error will be thrown if the command
-# isn't found.
-AC_DEFUN([FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL],
-[FP_ARG_WITH_PATH_GNU_PROG_GENERAL([$1], [$2], [$3], [yes], [yes])])
-
-# FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL_NOTARGET
-# --------------------
-# Same as FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL but don't prepend the target name
-# (used for LLVM).
-AC_DEFUN([FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL_NOTARGET],
-[FP_ARG_WITH_PATH_GNU_PROG_GENERAL([$1], [$2], [$3], [no], [yes])])
-
-
 # FP_PROG_CONTEXT_DIFF
 # --------------------
 # Figure out how to do context diffs. Sets the output variable ContextDiffCmd.
 # FP_PROG_CONTEXT_DIFF
 # --------------------
 # Figure out how to do context diffs. Sets the output variable ContextDiffCmd.
@@ -771,6 +796,16 @@ m4_popdef([fp_Cache])[]dnl
 ])# FP_CHECK_ALIGNMENT
 
 
 ])# FP_CHECK_ALIGNMENT
 
 
+
+# FP_CHECK_SIZEOF_AND_ALIGNMENT(TYPE)
+# ------------------------------------------------------------------
+# Combines AC_CHECK_SIZEOF and FP_CHECK_ALIGNMENT.
+AC_DEFUN([FP_CHECK_SIZEOF_AND_ALIGNMENT],
+[AC_CHECK_SIZEOF([$1])
+FP_CHECK_ALIGNMENT([$1])
+])# FP_CHECK_SIZEOF_AND_ALIGNMENT
+
+
 # FP_LEADING_UNDERSCORE
 # ---------------------
 # Test for determining whether symbol names have a leading underscore. We assume
 # FP_LEADING_UNDERSCORE
 # ---------------------
 # Test for determining whether symbol names have a leading underscore. We assume
@@ -782,30 +817,24 @@ m4_popdef([fp_Cache])[]dnl
 # checking for *no* leading underscore first. Sigh.  --SDM
 #
 # Similarly on OpenBSD, but this test doesn't help. -- dons
 # checking for *no* leading underscore first. Sigh.  --SDM
 #
 # Similarly on OpenBSD, but this test doesn't help. -- dons
+#
 AC_DEFUN([FP_LEADING_UNDERSCORE],
 [AC_CHECK_LIB([elf], [nlist], [LIBS="-lelf $LIBS"])
 AC_CACHE_CHECK([leading underscore in symbol names], [fptools_cv_leading_underscore], [
 # Hack!: nlist() under Digital UNIX insist on there being an _,
 # but symbol table listings shows none. What is going on here?!?
 AC_DEFUN([FP_LEADING_UNDERSCORE],
 [AC_CHECK_LIB([elf], [nlist], [LIBS="-lelf $LIBS"])
 AC_CACHE_CHECK([leading underscore in symbol names], [fptools_cv_leading_underscore], [
 # Hack!: nlist() under Digital UNIX insist on there being an _,
 # but symbol table listings shows none. What is going on here?!?
-#
-# Another hack: cygwin doesn't come with nlist.h , so we hardwire
-# the underscoredness of that "platform"
-case $HostPlatform in
-*openbsd*) # x86 openbsd is ELF from 3.4 >, meaning no leading uscore
-  case $build in
-    i386-*2\.@<:@0-9@:>@ | i386-*3\.@<:@0-3@:>@ ) fptools_cv_leading_underscore=yes ;;
-    *) fptools_cv_leading_underscore=no ;;
-  esac ;;
-alpha-dec-osf*) fptools_cv_leading_underscore=no;;
-*cygwin32) fptools_cv_leading_underscore=yes;;
-i386-unknown-mingw32) fptools_cv_leading_underscore=yes;;
-x86_64-unknown-mingw32) fptools_cv_leading_underscore=no;;
-
-    # HACK: Apple doesn't seem to provide nlist in the 64-bit-libraries
-x86_64-apple-darwin*) fptools_cv_leading_underscore=yes;;
-*-apple-ios) fptools_cv_leading_underscore=yes;;
-
-*) AC_RUN_IFELSE([AC_LANG_SOURCE([[#ifdef HAVE_NLIST_H
+case $TargetPlatform in
+    # Apples mach-o platforms use leading underscores
+    *-apple-*) fptools_cv_leading_underscore=yes;;
+    *linux-android*) fptools_cv_leading_underscore=no;;
+    *openbsd*) # x86 openbsd is ELF from 3.4 >, meaning no leading uscore
+      case $build in
+        i386-*2\.@<:@0-9@:>@ | i386-*3\.@<:@0-3@:>@ ) fptools_cv_leading_underscore=yes ;;
+        *) fptools_cv_leading_underscore=no ;;
+      esac ;;
+    i386-unknown-mingw32) fptools_cv_leading_underscore=yes;;
+    x86_64-unknown-mingw32) fptools_cv_leading_underscore=no;;
+    *) AC_RUN_IFELSE([AC_LANG_SOURCE([[#ifdef HAVE_NLIST_H
 #include <nlist.h>
 struct nlist xYzzY1[] = {{"xYzzY1", 0},{0}};
 struct nlist xYzzY2[] = {{"_xYzzY2", 0},{0}};
 #include <nlist.h>
 struct nlist xYzzY1[] = {{"xYzzY1", 0},{0}};
 struct nlist xYzzY2[] = {{"_xYzzY2", 0},{0}};
@@ -861,18 +890,20 @@ AS_IF([test "$fp_num1" $2 "$fp_num2"], [$4], [$5])[]dnl
 
 
 dnl
 
 
 dnl
-dnl Check for Happy and version.  If we're building GHC, then we need
-dnl at least Happy version 1.19.  If there's no installed Happy, we look
+dnl Check for Happy and version.
+dnl If there's no installed Happy, we look
 dnl for a happy source tree and point the build system at that instead.
 dnl for a happy source tree and point the build system at that instead.
+dnl If you increase the minimum version requirement, please also update:
+dnl https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Tools
 dnl
 AC_DEFUN([FPTOOLS_HAPPY],
 dnl
 AC_DEFUN([FPTOOLS_HAPPY],
-[FP_PATH_PROG(HappyCmd,happy,)
+[AC_PATH_PROG(HappyCmd,happy,)
 
 AC_CACHE_CHECK([for version of happy], fptools_cv_happy_version,
 changequote(, )dnl
 [if test x"$HappyCmd" != x; then
    fptools_cv_happy_version=`"$HappyCmd" -v |
 
 AC_CACHE_CHECK([for version of happy], fptools_cv_happy_version,
 changequote(, )dnl
 [if test x"$HappyCmd" != x; then
    fptools_cv_happy_version=`"$HappyCmd" -v |
-                         grep 'Happy Version' | sed -e 's/Happy Version \([^ ]*\).*/\1/g'` ;
+              grep 'Happy Version' | sed -e 's/Happy Version \([^ ]*\).*/\1/g'` ;
 else
    fptools_cv_happy_version="";
 fi;
 else
    fptools_cv_happy_version="";
 fi;
@@ -888,18 +919,19 @@ AC_SUBST(HappyVersion)
 ])
 
 dnl
 ])
 
 dnl
-dnl Check for Alex and version.  If we're building GHC, then we need
-dnl at least Alex version 2.1.1.
+dnl Check for Alex and version.
+dnl If you increase the minimum version requirement, please also update:
+dnl https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Tools
 dnl
 AC_DEFUN([FPTOOLS_ALEX],
 [
 dnl
 AC_DEFUN([FPTOOLS_ALEX],
 [
-FP_PATH_PROG(AlexCmd,alex,)
+AC_PATH_PROG(AlexCmd,alex,)
 
 AC_CACHE_CHECK([for version of alex], fptools_cv_alex_version,
 changequote(, )dnl
 [if test x"$AlexCmd" != x; then
    fptools_cv_alex_version=`"$AlexCmd" -v |
 
 AC_CACHE_CHECK([for version of alex], fptools_cv_alex_version,
 changequote(, )dnl
 [if test x"$AlexCmd" != x; then
    fptools_cv_alex_version=`"$AlexCmd" -v |
-                         grep 'Alex [Vv]ersion' | sed -e 's/Alex [Vv]ersion \([0-9\.]*\).*/\1/g'` ;
+              grep 'Alex [Vv]ersion' | sed -e 's/Alex [Vv]ersion \([0-9\.]*\).*/\1/g'` ;
 else
    fptools_cv_alex_version="";
 fi;
 else
    fptools_cv_alex_version="";
 fi;
@@ -966,15 +998,14 @@ AC_SUBST([LdHasBuildId])
 # -----------------
 # Sets the output variable LdIsGNULd to YES or NO, depending on whether it is
 # GNU ld or not.
 # -----------------
 # Sets the output variable LdIsGNULd to YES or NO, depending on whether it is
 # GNU ld or not.
-AC_DEFUN([FP_PROG_LD_IS_GNU],
-[
+AC_DEFUN([FP_PROG_LD_IS_GNU],[
 AC_CACHE_CHECK([whether ld is GNU ld], [fp_cv_gnu_ld],
 AC_CACHE_CHECK([whether ld is GNU ld], [fp_cv_gnu_ld],
-[if ${LdCmd} --version 2> /dev/null | grep "GNU" > /dev/null 2>&1; then
-  fp_cv_gnu_ld=yes
+[[if ${LdCmd} --version 2> /dev/null | grep "GNU" > /dev/null 2>&1; then
+  fp_cv_gnu_ld=YES
 else
 else
-  fp_cv_gnu_ld=no
-fi])
-AC_SUBST([LdIsGNULd], [`echo $fp_cv_gnu_ld | sed 'y/yesno/YESNO/'`])
+  fp_cv_gnu_ld=NO
+fi]])
+AC_SUBST([LdIsGNULd],["$fp_cv_gnu_ld"])
 ])# FP_PROG_LD_IS_GNU
 
 
 ])# FP_PROG_LD_IS_GNU
 
 
@@ -1037,9 +1068,11 @@ AC_SUBST([LdHasFilelist])
 
 # FP_PROG_AR
 # ----------
 
 # FP_PROG_AR
 # ----------
-# Sets fp_prog_ar to a (non-Cygwin) path to ar. Exits if no ar can be found
+# Sets fp_prog_ar to a path to ar. Exits if no ar can be found
 AC_DEFUN([FP_PROG_AR],
 AC_DEFUN([FP_PROG_AR],
-[FP_PATH_PROG([fp_prog_ar], [ar])
+[if test -z "$fp_prog_ar"; then
+  AC_PATH_PROG([fp_prog_ar], [ar])
+fi
 if test -z "$fp_prog_ar"; then
   AC_MSG_ERROR([cannot find ar in your PATH, no idea how to make a library])
 fi
 if test -z "$fp_prog_ar"; then
   AC_MSG_ERROR([cannot find ar in your PATH, no idea how to make a library])
 fi
@@ -1091,7 +1124,7 @@ AC_SUBST([ArSupportsAtFile], [`echo $fp_prog_ar_supports_atfile | tr 'a-z' 'A-Z'
 # FP_PROG_AR_ARGS
 # ---------------
 # Sets fp_prog_ar_args to the arguments for ar and the output variable ArCmd
 # FP_PROG_AR_ARGS
 # ---------------
 # Sets fp_prog_ar_args to the arguments for ar and the output variable ArCmd
-# to a non-Cygwin invocation of ar including these arguments.
+# to an invocation of ar including these arguments.
 AC_DEFUN([FP_PROG_AR_ARGS],
 [AC_REQUIRE([FP_PROG_AR_IS_GNU])
 AC_CACHE_CHECK([for ar arguments], [fp_cv_prog_ar_args],
 AC_DEFUN([FP_PROG_AR_ARGS],
 [AC_REQUIRE([FP_PROG_AR_IS_GNU])
 AC_CACHE_CHECK([for ar arguments], [fp_cv_prog_ar_args],
@@ -1116,6 +1149,9 @@ else
   fi
 fi])
 fp_prog_ar_args=$fp_cv_prog_ar_args
   fi
 fi])
 fp_prog_ar_args=$fp_cv_prog_ar_args
+if test "$HostOS" != "mingw32"; then
+    ArCmd = "$(cygpath -m $ArCmd)"
+fi
 AC_SUBST([ArCmd], ["$fp_prog_ar"])
 AC_SUBST([ArArgs], ["$fp_prog_ar_args"])
 
 AC_SUBST([ArCmd], ["$fp_prog_ar"])
 AC_SUBST([ArArgs], ["$fp_prog_ar_args"])
 
@@ -1137,7 +1173,7 @@ AC_DEFUN([FP_PROG_AR_NEEDS_RANLIB],[
     if test $fp_prog_ar_is_gnu = yes
     then
         fp_cv_prog_ar_needs_ranlib=no
     if test $fp_prog_ar_is_gnu = yes
     then
         fp_cv_prog_ar_needs_ranlib=no
-    elif test "$TargetOS_CPP" = "darwin"
+    elif test "$TargetVendor_CPP" = "apple"
     then
         # It's quite tedious to check for Apple's crazy timestamps in
         # .a files, so we hardcode it.
     then
         # It's quite tedious to check for Apple's crazy timestamps in
         # .a files, so we hardcode it.
@@ -1184,6 +1220,7 @@ then
   AC_MSG_ERROR([gcc is required])
 fi
 GccLT34=NO
   AC_MSG_ERROR([gcc is required])
 fi
 GccLT34=NO
+GccLT44=NO
 GccLT46=NO
 AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
 [
 GccLT46=NO
 AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
 [
@@ -1194,10 +1231,12 @@ AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
     # isn't a very good reason for that, but for now just make configure
     # fail.
     FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [3.4], GccLT34=YES)
     # isn't a very good reason for that, but for now just make configure
     # fail.
     FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [3.4], GccLT34=YES)
+    FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.4], GccLT44=YES)
     FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.6], GccLT46=YES)
 ])
 AC_SUBST([GccVersion], [$fp_cv_gcc_version])
 AC_SUBST(GccLT34)
     FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.6], GccLT46=YES)
 ])
 AC_SUBST([GccVersion], [$fp_cv_gcc_version])
 AC_SUBST(GccLT34)
+AC_SUBST(GccLT44)
 AC_SUBST(GccLT46)
 ])# FP_GCC_VERSION
 
 AC_SUBST(GccLT46)
 ])# FP_GCC_VERSION
 
@@ -1231,6 +1270,26 @@ AC_SUBST(GccIsClang)
 rm -f conftest.txt
 ])
 
 rm -f conftest.txt
 ])
 
+# FP_GCC_SUPPORTS_NO_PIE
+# ----------------------
+# Does gcc support the -no-pie option? If so we should pass it to gcc when
+# joining objects since -pie may be enabled by default.
+AC_DEFUN([FP_GCC_SUPPORTS_NO_PIE],
+[
+   AC_REQUIRE([AC_PROG_CC])
+   AC_MSG_CHECKING([whether GCC supports -no-pie])
+   echo 'int main() { return 0; }' > conftest.c
+   # Some GCC versions only warn when passed an unrecognized flag.
+   if $CC -no-pie -x c /dev/null -dM -E > conftest.txt 2>&1 && ! grep -i unrecognized conftest.txt > /dev/null 2>&1; then
+       CONF_GCC_SUPPORTS_NO_PIE=YES
+       AC_MSG_RESULT([yes])
+   else
+       CONF_GCC_SUPPORTS_NO_PIE=NO
+       AC_MSG_RESULT([no])
+   fi
+   rm -f conftest.c conftest.o conftest
+])
+
 dnl Small feature test for perl version. Assumes PerlCmd
 dnl contains path to perl binary.
 dnl
 dnl Small feature test for perl version. Assumes PerlCmd
 dnl contains path to perl binary.
 dnl
@@ -1267,15 +1326,6 @@ echo foo > conftest.txt
 $fp_prog_find conftest.txt -print > conftest.out 2>&1
 if grep '^conftest.txt$' conftest.out > /dev/null 2>&1 ; then
   # OK, looks like a real "find".
 $fp_prog_find conftest.txt -print > conftest.out 2>&1
 if grep '^conftest.txt$' conftest.out > /dev/null 2>&1 ; then
   # OK, looks like a real "find".
-  case $HostPlatform in
-    *mingw32)
-      if test x${OSTYPE} != xmsys
-      then
-           fp_prog_find="`cygpath --mixed ${fp_prog_find}`"
-        AC_MSG_NOTICE([normalized find command to $fp_prog_find])
-      fi ;;
-    *) ;;
-  esac
   FindCmd="$fp_prog_find"
 else
   # Found a poor WinDoze version of "find", ignore it.
   FindCmd="$fp_prog_find"
 else
   # Found a poor WinDoze version of "find", ignore it.
@@ -1387,124 +1437,6 @@ AS_IF([test AS_VAR_GET(fp_func) = yes],
 AS_VAR_POPDEF([fp_func])dnl
 ])# FP_CHECK_FUNC
 
 AS_VAR_POPDEF([fp_func])dnl
 ])# FP_CHECK_FUNC
 
-
-# FP_GEN_DOCBOOK_XML
-# ------------------
-# Generates a DocBook XML V4.5 document in conftest.xml.
-#
-# It took a lot of experimentation to find a document that will cause
-# xsltproc to fail with an error code when the relevant
-# stylesheets/DTDs are not found.  I couldn't make xsltproc fail with
-# a single-file document, it seems a multi-file document is needed.
-# -- SDM 2009-06-03
-#
-AC_DEFUN([FP_GEN_DOCBOOK_XML],
-[rm -f conftest.xml conftest-book.xml
-cat > conftest.xml << EOF
-<?xml version="1.0" encoding="iso-8859-1"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [[
-<!ENTITY conftest-book SYSTEM "conftest-book.xml">
-]]>
-<book id="test">
-&conftest-book;
-</book>
-EOF
-cat >conftest-book.xml << EOF
-<?xml version="1.0" encoding="iso-8859-1"?>
-  <title>A DocBook &ldquo;Test Document&rdquo;</title>
-  <chapter id="id-one">
-    <title>A Chapter Title</title>
-    <para>This is a paragraph, referencing <xref linkend="id-two"/>.</para>
-  </chapter>
-  <chapter id="id-two">
-    <title>Another Chapter Title</title>
-    <para>This is another paragraph, referencing <xref linkend="id-one"/>.</para>
-  </chapter>
-EOF
-]) # FP_GEN_DOCBOOK_XML
-
-
-# FP_PROG_DBLATEX
-# ----------------
-# Sets the output variable DblatexCmd to the full path of dblatex,
-# which we use for building PDF and PS docs.
-# DblatexCmd is empty if dblatex could not be found.
-AC_DEFUN([FP_PROG_DBLATEX],
-[FP_PATH_PROG([DblatexCmd], [dblatex])
-if test -z "$DblatexCmd"; then
-  AC_MSG_WARN([cannot find dblatex in your PATH, you will not be able to build the PDF and PS documentation])
-fi
-])# FP_PROG_DBLATEX
-
-
-# FP_PROG_XSLTPROC
-# ----------------
-# Sets the output variable XsltprocCmd to the full path of the XSLT processor
-# xsltproc. XsltprocCmd is empty if xsltproc could not be found.
-AC_DEFUN([FP_PROG_XSLTPROC],
-[FP_PATH_PROG([XsltprocCmd], [xsltproc])
-if test -z "$XsltprocCmd"; then
-  AC_MSG_WARN([cannot find xsltproc in your PATH, you will not be able to build the HTML documentation])
-fi
-])# FP_PROG_XSLTPROC
-
-
-# FP_DOCBOOK_XSL
-# ----------------------------
-# Check that we can process a DocBook XML document to HTML using xsltproc.
-AC_DEFUN([FP_DOCBOOK_XSL],
-[AC_REQUIRE([FP_PROG_XSLTPROC])dnl
-if test -n "$XsltprocCmd"; then
-  AC_CACHE_CHECK([for DocBook XSL stylesheet], fp_cv_dir_docbook_xsl,
-  [FP_GEN_DOCBOOK_XML
-  fp_cv_dir_docbook_xsl=no
-  if $XsltprocCmd --nonet http://docbook.sourceforge.net/release/xsl/current/html/chunk.xsl conftest.xml > /dev/null 2>&1; then
-     fp_cv_dir_docbook_xsl=yes
-  fi
-  rm -rf conftest*])
-fi
-if test x"$fp_cv_dir_docbook_xsl" = xno; then
-  AC_MSG_WARN([cannot find DocBook XSL stylesheets, you will not be able to build the documentation])
-  HAVE_DOCBOOK_XSL=NO
-else
-  HAVE_DOCBOOK_XSL=YES
-fi
-AC_SUBST([HAVE_DOCBOOK_XSL])
-])# FP_DOCBOOK_XSL
-
-
-# FP_PROG_XMLLINT
-# ----------------
-# Sets the output variable XmllintCmd to the full path of the XSLT processor
-# xmllint. XmllintCmd is empty if xmllint could not be found.
-AC_DEFUN([FP_PROG_XMLLINT],
-[FP_PATH_PROG([XmllintCmd], [xmllint])
-if test -z "$XmllintCmd"; then
-  AC_MSG_WARN([cannot find xmllint in your PATH, you will not be able to validate your documentation])
-fi
-])# FP_PROG_XMLLINT
-
-
-# FP_CHECK_DOCBOOK_DTD
-# --------------------
-AC_DEFUN([FP_CHECK_DOCBOOK_DTD],
-[AC_REQUIRE([FP_PROG_XMLLINT])dnl
-if test -n "$XmllintCmd"; then
-  AC_MSG_CHECKING([for DocBook DTD])
-  FP_GEN_DOCBOOK_XML
-  if $XmllintCmd --nonet --valid --noout conftest.xml ; then
-    AC_MSG_RESULT([ok])
-  else
-    AC_MSG_RESULT([failed])
-    AC_MSG_WARN([cannot find a DTD for DocBook XML V4.5, you will not be able to validate your documentation])
-    AC_MSG_WARN([check your XML_CATALOG_FILES environment variable and/or /etc/xml/catalog])
-  fi
-  rm -rf conftest*
-fi
-])# FP_CHECK_DOCBOOK_DTD
-
-
 # FP_PROG_GHC_PKG
 # ----------------
 # Try to find a ghc-pkg matching the ghc mentioned in the environment variable
 # FP_PROG_GHC_PKG
 # ----------------
 # Try to find a ghc-pkg matching the ghc mentioned in the environment variable
@@ -1517,7 +1449,7 @@ AC_DEFUN([FP_PROG_GHC_PKG],
 # so we sed off -stage[0-9]$. However, if we are told to use
 # ghc-6.12.1 then we want to use ghc-pkg-6.12.1, so we keep any
 # other suffix.
 # so we sed off -stage[0-9]$. However, if we are told to use
 # ghc-6.12.1 then we want to use ghc-pkg-6.12.1, so we keep any
 # other suffix.
-fp_ghc_pkg_guess=`echo $WithGhc | sed -e 's/-stage@<:@0-9@:>@$//' -e 's,ghc\(@<:@^/\\@:>@*\)$,ghc-pkg\1,'`
+fp_ghc_pkg_guess=`echo "$WithGhc" | sed -e 's/-stage@<:@0-9@:>@$//' -e 's,ghc\(@<:@^/\\@:>@*\)$,ghc-pkg\1,'`
 if "$fp_ghc_pkg_guess" list > /dev/null 2>&1; then
   fp_cv_matching_ghc_pkg=$fp_ghc_pkg_guess
 else
 if "$fp_ghc_pkg_guess" list > /dev/null 2>&1; then
   fp_cv_matching_ghc_pkg=$fp_ghc_pkg_guess
 else
@@ -1543,6 +1475,9 @@ AC_CACHE_CHECK([for extra options to pass gcc when compiling via C], [fp_cv_gcc_
  FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-ge], [3.4],
   [fp_cv_gcc_extra_opts="$fp_cv_gcc_extra_opts -fwrapv"],
   [])
  FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-ge], [3.4],
   [fp_cv_gcc_extra_opts="$fp_cv_gcc_extra_opts -fwrapv"],
   [])
+ FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-ge], [4.0],
+  [fp_cv_gcc_extra_opts="$fp_cv_gcc_extra_opts -fno-builtin"],
+  [])
 ])
 AC_SUBST([GccExtraViaCOpts],$fp_cv_gcc_extra_opts)
 ])
 ])
 AC_SUBST([GccExtraViaCOpts],$fp_cv_gcc_extra_opts)
 ])
@@ -1559,10 +1494,11 @@ if test "$RELEASE" = "NO"; then
         AC_MSG_RESULT(given $PACKAGE_VERSION)
     elif test -d .git; then
         changequote(, )dnl
         AC_MSG_RESULT(given $PACKAGE_VERSION)
     elif test -d .git; then
         changequote(, )dnl
-        ver_date=`git log -n 1 --date=short --pretty=format:%ci | cut -d ' ' -f 1 | tr -d -`
+        ver_posixtime=`git log -1 --pretty=format:%ct`
+        ver_date=`perl -MPOSIX -e "print strftime('%Y%m%d', gmtime($ver_posixtime));"`
         if echo $ver_date | grep '^[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]$' 2>&1 >/dev/null; then true; else
         changequote([, ])dnl
         if echo $ver_date | grep '^[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]$' 2>&1 >/dev/null; then true; else
         changequote([, ])dnl
-                AC_MSG_ERROR([failed to detect version date: check that git is in your path])
+                AC_MSG_ERROR([failed to detect version date: check that git and perl are in your path])
         fi
         PACKAGE_VERSION=${PACKAGE_VERSION}.$ver_date
         AC_MSG_RESULT(inferred $PACKAGE_VERSION)
         fi
         PACKAGE_VERSION=${PACKAGE_VERSION}.$ver_date
         AC_MSG_RESULT(inferred $PACKAGE_VERSION)
@@ -1581,6 +1517,7 @@ if test "$RELEASE" = "NO"; then
         dnl less likely to go wrong.
         PACKAGE_VERSION=${PACKAGE_VERSION}.`date +%Y%m%d`
     fi
         dnl less likely to go wrong.
         PACKAGE_VERSION=${PACKAGE_VERSION}.`date +%Y%m%d`
     fi
+fi
 
     AC_MSG_CHECKING([for GHC Git commit id])
     if test -d .git; then
 
     AC_MSG_CHECKING([for GHC Git commit id])
     if test -d .git; then
@@ -1598,7 +1535,6 @@ if test "$RELEASE" = "NO"; then
         PACKAGE_GIT_COMMIT_ID="0000000000000000000000000000000000000000"
     fi
 
         PACKAGE_GIT_COMMIT_ID="0000000000000000000000000000000000000000"
     fi
 
-fi
 
 # Some renamings
 AC_SUBST([ProjectName], [$PACKAGE_NAME])
 
 # Some renamings
 AC_SUBST([ProjectName], [$PACKAGE_NAME])
@@ -1633,8 +1569,22 @@ AC_SUBST([ProjectPatchLevel2])
 ProjectPatchLevel=`echo $ProjectPatchLevel | sed 's/\.//'`
 
 AC_SUBST([ProjectPatchLevel])
 ProjectPatchLevel=`echo $ProjectPatchLevel | sed 's/\.//'`
 
 AC_SUBST([ProjectPatchLevel])
-])# FP_SETUP_PROJECT_VERSION
 
 
+# The version of the GHC package changes every day, since the
+# patchlevel is the current date.  We don't want to force
+# recompilation of the entire compiler when this happens, so for
+# GHC HEAD we omit the patchlevel from the package version number.
+#
+# The ProjectPatchLevel1 > 20000000 iff GHC HEAD. If it's for a stable
+# release like 7.10.1 or for a release candidate such as 7.10.1.20141224
+# then we don't omit the patchlevel components.
+
+ProjectVersionMunged="$ProjectVersion"
+if test "$ProjectPatchLevel1" -gt 20000000; then
+  ProjectVersionMunged="${VERSION_MAJOR}.${VERSION_MINOR}"
+fi
+AC_SUBST([ProjectVersionMunged])
+])# FP_SETUP_PROJECT_VERSION
 
 # Check for a working timer_create().  We need a pretty detailed check
 # here, because there exist partially-working implementations of
 
 # Check for a working timer_create().  We need a pretty detailed check
 # here, because there exist partially-working implementations of
@@ -1649,7 +1599,7 @@ then
   then
     # We can't test timer_create when we're cross-compiling, so we
     # optimistiaclly assume that it actually works properly.
   then
     # We can't test timer_create when we're cross-compiling, so we
     # optimistiaclly assume that it actually works properly.
-    AC_DEFINE([USE_TIMER_CREATE], 1,  [Define to 1 if we can use timer_create(CLOCK_PROCESS_CPUTIME_ID,...)])
+    AC_DEFINE([USE_TIMER_CREATE], 1,  [Define to 1 if we can use timer_create(CLOCK_REALTIME,...)])
   else
   AC_CACHE_CHECK([for a working timer_create(CLOCK_REALTIME)],
     [fptools_cv_timer_create_works],
   else
   AC_CACHE_CHECK([for a working timer_create(CLOCK_REALTIME)],
     [fptools_cv_timer_create_works],
@@ -1710,52 +1660,23 @@ int main(int argc, char *argv[])
     }
     alarm(1);
 
     }
     alarm(1);
 
-    if (timer_create(CLOCK_PROCESS_CPUTIME_ID, &ev, &timer) != 0) {
-        fprintf(stderr,"No CLOCK_PROCESS_CPUTIME_ID timer\n");
-       exit(1);
-    }
-
-    it.it_value.tv_sec = 0;
-    it.it_value.tv_nsec = 1;
-    it.it_interval = it.it_value;
-    if (timer_settime(timer, 0, &it, NULL) != 0) {
-        fprintf(stderr,"settime problem\n");
-        exit(4);
-    }
-
-    tock = 0;
-
-    for(n = 3; n < 20000; n++){
-        for(m = 2; m <= n/2; m++){
-            if (!(n%m)) count++;
-            if (tock) goto out;
-        }
-    }
-out:
-
-    if (!tock) {
-        fprintf(stderr,"no CLOCK_PROCESS_CPUTIME_ID signal\n");
-        exit(5);
-    }
-
-    timer_delete(timer);
-
     if (timer_create(CLOCK_REALTIME, &ev, &timer) != 0) {
         fprintf(stderr,"No CLOCK_REALTIME timer\n");
         exit(2);
     }
 
     if (timer_create(CLOCK_REALTIME, &ev, &timer) != 0) {
         fprintf(stderr,"No CLOCK_REALTIME timer\n");
         exit(2);
     }
 
+    tock = 0;
+
     it.it_value.tv_sec = 0;
     it.it_value.tv_sec = 0;
-    it.it_value.tv_nsec = 1000000;
+    it.it_value.tv_nsec = 1000000; // 1ms
     it.it_interval = it.it_value;
     if (timer_settime(timer, 0, &it, NULL) != 0) {
         fprintf(stderr,"settime problem\n");
         exit(4);
     }
 
     it.it_interval = it.it_value;
     if (timer_settime(timer, 0, &it, NULL) != 0) {
         fprintf(stderr,"settime problem\n");
         exit(4);
     }
 
-    tock = 0;
-
-    usleep(3000);
+    // some environments have coarse scheduler/timer granularity of ~10ms and worse
+    usleep(100000); // 100ms
 
     if (!tock) {
         fprintf(stderr,"no CLOCK_REALTIME signal\n");
 
     if (!tock) {
         fprintf(stderr,"no CLOCK_REALTIME signal\n");
@@ -1772,7 +1693,7 @@ out:
   ])
 case $fptools_cv_timer_create_works in
     yes) AC_DEFINE([USE_TIMER_CREATE], 1,
   ])
 case $fptools_cv_timer_create_works in
     yes) AC_DEFINE([USE_TIMER_CREATE], 1,
-                   [Define to 1 if we can use timer_create(CLOCK_PROCESS_CPUTIME_ID,...)]);;
+                   [Define to 1 if we can use timer_create(CLOCK_REALTIME,...)]);;
 esac
   fi
 fi
 esac
   fi
 fi
@@ -1826,37 +1747,38 @@ AC_DEFUN([FP_GMP],
   AC_SUBST(GMP_LIB_DIRS)
 ])# FP_GMP
 
   AC_SUBST(GMP_LIB_DIRS)
 ])# FP_GMP
 
-# --------------------------------------------------------------
-# Calculate absolute path to build tree
-# --------------------------------------------------------------
+# FP_CURSES
+# -------------
+AC_DEFUN([FP_CURSES],
+[
+  dnl--------------------------------------------------------------------
+  dnl * Deal with arguments telling us curses is somewhere odd
+  dnl--------------------------------------------------------------------
 
 
-AC_DEFUN([FP_INTREE_GHC_PWD],[
-AC_MSG_NOTICE(Building in-tree ghc-pwd)
-    dnl This would be
-    dnl     make -C utils/ghc-pwd clean && make -C utils/ghc-pwd
-    dnl except we don't want to have to know what make is called. Sigh.
-    rm -rf utils/ghc-pwd/dist-boot
-    mkdir  utils/ghc-pwd/dist-boot
-    dnl If special linker flags are needed to build things, then allow
-    dnl the user to pass them in via LDFLAGS.
-    changequote(, )dnl
-    GHC_LDFLAGS=`perl -e 'foreach (@ARGV) { print "-optl$_ " }' -- $LDFLAGS`
-    changequote([, ])dnl
-    if ! "$WithGhc" $GHC_LDFLAGS -v0 -no-user-$GHC_PACKAGE_DB_FLAG -hidir utils/ghc-pwd/dist-boot -odir utils/ghc-pwd/dist-boot -stubdir utils/ghc-pwd/dist-boot --make utils/ghc-pwd/Main.hs -o utils/ghc-pwd/dist-boot/ghc-pwd
-    then
-        AC_MSG_ERROR([Building ghc-pwd failed])
-    fi
+  AC_ARG_WITH([curses-libraries],
+    [AC_HELP_STRING([--with-curses-libraries],
+      [directory containing curses libraries])],
+      [CURSES_LIB_DIRS=$withval])
 
 
-    GHC_PWD=utils/ghc-pwd/dist-boot/ghc-pwd
-])
+  AC_SUBST(CURSES_INCLUDE_DIRS)
+  AC_SUBST(CURSES_LIB_DIRS)
+])# FP_CURSES
 
 
-AC_DEFUN([FP_BINDIST_GHC_PWD],[
-    GHC_PWD=utils/ghc-pwd/dist-install/build/tmp/ghc-pwd-bindist
-])
+# --------------------------------------------------------------
+# Calculate absolute path to build tree
+# --------------------------------------------------------------
 
 AC_DEFUN([FP_FIND_ROOT],[
 AC_MSG_CHECKING(for path to top of build tree)
 
 AC_DEFUN([FP_FIND_ROOT],[
 AC_MSG_CHECKING(for path to top of build tree)
-    hardtop=`$GHC_PWD`
+    if test "$windows" = YES
+    then
+      dnl Make sure this is a c:/foo/bar (mixed) style path. Some parts of
+      dnl the build system might depend on it (such as the sed expression
+      dnl `"s|$(TOP)/||i"` in addCFileDeps in rules/build-dependencies.mk).
+      hardtop=$(cygpath -m "$(pwd)")
+    else
+      hardtop=$(pwd)
+    fi
 
     dnl Remove common automounter nonsense
     hardtop=`echo $hardtop | sed 's|^/tmp_mnt.*\(/local/.*\)$|\1|' | sed 's|^/tmp_mnt/|/|'`
 
     dnl Remove common automounter nonsense
     hardtop=`echo $hardtop | sed 's|^/tmp_mnt.*\(/local/.*\)$|\1|' | sed 's|^/tmp_mnt/|/|'`
@@ -1936,6 +1858,9 @@ case "$1" in
   s390*)
     $2="s390"
     ;;
   s390*)
     $2="s390"
     ;;
+  sh4)
+    $2="sh4"
+    ;;
   sparc64*)
     $2="sparc64"
     ;;
   sparc64*)
     $2="sparc64"
     ;;
@@ -1966,6 +1891,9 @@ AC_DEFUN([GHC_CONVERT_VENDOR],[
   softfloat) # like armv5tel-softfloat-linux-gnueabi
     $2="unknown"
     ;;
   softfloat) # like armv5tel-softfloat-linux-gnueabi
     $2="unknown"
     ;;
+  hardfloat) # like armv7a-hardfloat-linux-gnueabi
+    $2="unknown"
+    ;;
   *)
     #pass thru by default
     $2="$1"
   *)
     #pass thru by default
     $2="$1"
@@ -1977,12 +1905,11 @@ AC_DEFUN([GHC_CONVERT_VENDOR],[
 # --------------------------------
 # converts os from gnu to ghc naming, and assigns the result to $target_var
 AC_DEFUN([GHC_CONVERT_OS],[
 # --------------------------------
 # converts os from gnu to ghc naming, and assigns the result to $target_var
 AC_DEFUN([GHC_CONVERT_OS],[
-case "$1-$2" in
-  darwin10-arm|darwin11-i386|darwin14-aarch64)
-    $3="ios"
-    ;;
-  *)
     case "$1" in
     case "$1" in
+      # watchos and tvos are ios variants as of May 2017.
+      ios|watchos|tvos)
+        $3="ios"
+        ;;
       linux-android*)
         $3="linux-android"
         ;;
       linux-android*)
         $3="linux-android"
         ;;
@@ -1990,9 +1917,15 @@ case "$1-$2" in
         $3="linux"
         ;;
       # As far as I'm aware, none of these have relevant variants
         $3="linux"
         ;;
       # As far as I'm aware, none of these have relevant variants
-      freebsd|netbsd|openbsd|dragonfly|osf1|osf3|hpux|linuxaout|kfreebsdgnu|freebsd2|solaris2|cygwin32|mingw32|darwin|gnu|nextstep2|nextstep3|sunos4|ultrix|irix|aix|haiku)
+      freebsd|netbsd|openbsd|dragonfly|hpux|linuxaout|kfreebsdgnu|freebsd2|solaris2|mingw32|darwin|gnu|nextstep2|nextstep3|sunos4|ultrix|haiku)
         $3="$1"
         ;;
         $3="$1"
         ;;
+      aix*) # e.g. powerpc-ibm-aix7.1.3.0
+        $3="aix"
+        ;;
+      darwin*) # e.g. aarch64-apple-darwin14
+        $3="darwin"
+        ;;
       freebsd*) # like i686-gentoo-freebsd7
                 #      i686-gentoo-freebsd8
                 #      i686-gentoo-freebsd8.2
       freebsd*) # like i686-gentoo-freebsd7
                 #      i686-gentoo-freebsd8
                 #      i686-gentoo-freebsd8.2
@@ -2006,8 +1939,6 @@ case "$1-$2" in
         exit 1
         ;;
       esac
         exit 1
         ;;
       esac
-      ;;
-  esac
 ])
 
 # BOOTSTRAPPING_GHC_INFO_FIELD
 ])
 
 # BOOTSTRAPPING_GHC_INFO_FIELD
@@ -2039,7 +1970,7 @@ AC_SUBST(LIBRARY_[]translit([$1], [-], [_])[]_VERSION)
 # --------------------------------
 # Gets the version number of XCode, if on a Mac
 AC_DEFUN([XCODE_VERSION],[
 # --------------------------------
 # Gets the version number of XCode, if on a Mac
 AC_DEFUN([XCODE_VERSION],[
-    if test "$TargetOS_CPP" = "darwin"
+    if test "$TargetVendor_CPP" = "apple"
     then
         AC_MSG_CHECKING(XCode version)
         XCodeVersion=`xcodebuild -version | grep Xcode | sed "s/Xcode //"`
     then
         AC_MSG_CHECKING(XCode version)
         XCodeVersion=`xcodebuild -version | grep Xcode | sed "s/Xcode //"`
@@ -2067,65 +1998,102 @@ AC_DEFUN([XCODE_VERSION],[
 # are installed with a version suffix (e.g., llc-3.1).
 #
 # $1 = the variable to set
 # are installed with a version suffix (e.g., llc-3.1).
 #
 # $1 = the variable to set
-# $2 = the with option name
-# $3 = the command to look for
+# $2 = the command to look for
+# $3 = the version of the command to look for
 #
 AC_DEFUN([FIND_LLVM_PROG],[
 #
 AC_DEFUN([FIND_LLVM_PROG],[
-    FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL_NOTARGET([$1], [$2], [$3])
-    if test "$$1" == ""; then
-        save_IFS=$IFS
-        IFS=":;"
-        for p in ${PATH}; do
-            if test -d "${p}"; then
-                if test "$windows" = YES; then
-                    $1=`${FindCmd} "${p}" -type f -maxdepth 1 -regex '.*/$3-[[0-9]]\.[[0-9]]' -or -type l -maxdepth 1 -regex '.*/$3-[[0-9]]\.[[0-9]]' | ${SortCmd} -n | tail -1`
-                else
-                    $1=`${FindCmd} "${p}" -type f -perm \111 -maxdepth 1 -regex '.*/$3-[[0-9]]\.[[0-9]]' -or -type l -perm \111 -maxdepth 1 -regex '.*/$3-[[0-9]]\.[[0-9]]' | ${SortCmd} -n | tail -1`
-                fi
-                if test -n "$$1"; then
-                    break
-                fi
-            fi
-        done
-        IFS=$save_IFS
+    # Test for program with and without version name.
+    AC_CHECK_TOOLS([$1], [$2-$3 $2])
+    if test "$$1" != ":"; then
+        AC_MSG_CHECKING([$$1 is version $3])
+        if test `$$1 --version | grep -c "version $3"` -gt 0 ; then
+            AC_MSG_RESULT(yes)
+        else
+            AC_MSG_RESULT(no)
+            $1=""
+        fi
     fi
 ])
 
     fi
 ])
 
-# FIND_GCC()
+# CHECK_LD_COPY_BUG()
+# -------------------
+# Check for binutils bug #16177 present in some versions of the bfd ld
+# implementation affecting ARM relocations.
+# https://sourceware.org/bugzilla/show_bug.cgi?id=16177
+#
+# $1 = the platform
+#
+AC_DEFUN([CHECK_LD_COPY_BUG],[
+    case $1 in
+      arm*linux*)
+        AC_CHECK_TARGET_TOOL([READELF], [readelf])
+        AC_CHECK_TARGET_TOOL([AS], [as])
+        AC_MSG_CHECKING([for ld bug 16177])
+        cat >actest.s <<-EOF
+          .globl _start
+          .p2align 4
+        _start:
+          bkpt
+
+        .data
+          .globl data_object
+        object_reference:
+          .long data_object
+          .size object_reference, 4
+EOF
+
+        cat >aclib.s <<-EOF
+          .data
+          .globl data_object
+          .type data_object, %object
+          .size data_object, 4
+        data_object:
+            .long 123
+EOF
+
+        $AS -o aclib.o aclib.s
+        $LD -shared -o aclib.so aclib.o
+
+        $AS -o actest.o actest.s
+        $LD -o actest actest.o aclib.so
+
+        if $READELF -r actest | grep R_ARM_COPY > /dev/null; then
+            AC_MSG_RESULT([affected])
+            AC_MSG_ERROR(
+              [Your linker is affected by binutils #16177, which
+               critically breaks linkage of GHC objects. Please either upgrade
+               binutils or supply a different linker with the LD environment
+               variable.])
+        else
+            AC_MSG_RESULT([unaffected])
+        fi
+
+        rm -f aclib.s aclib.o aclib.so actest.s actest.o actest
+        ;;
+      *)
+        ;;
+    esac
+])
+
+# FIND_GHC_BOOTSTRAP_PROG()
 # --------------------------------
 # --------------------------------
-# Finds where gcc is
+# Parse the bootstrap GHC's compier settings file for the location of things
+# like the `llc` and `opt` commands.
 #
 # $1 = the variable to set
 #
 # $1 = the variable to set
-# $2 = the with option name
-# $3 = the command to look for
-AC_DEFUN([FIND_GCC],[
-    if test "$TargetOS_CPP" = "darwin" &&
-       test "$XCodeVersion1" -eq 4 &&
-       test "$XCodeVersion2" -lt 2
-    then
-        # In Xcode 4.1, 'gcc-4.2' is the gcc legacy backend (rather
-        # than the LLVM backend). We prefer the legacy gcc, but in
-        # Xcode 4.2 'gcc-4.2' was removed.
-        FP_ARG_WITH_PATH_GNU_PROG([$1], [gcc-4.2], [gcc-4.2])
-    elif test "$windows" = YES
-    then
-        $1="$CC"
+# $2 = The bootstrap compiler.
+# $3 = The string to grep for to find the correct line.
+#
+AC_DEFUN([FIND_GHC_BOOTSTRAP_PROG],[
+    BootstrapTmpCmd=`grep $3 $($2 --print-libdir)/settings 2>/dev/null | sed 's/.*", "//;s/".*//'`
+    if test -n "$BootstrapTmpCmd" && test `basename $BootstrapTmpCmd` = $BootstrapTmpCmd ; then
+        AC_PATH_PROG([$1], [$BootstrapTmpCmd], "")
     else
     else
-        FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL([$1], [$2], [$3])
-        # From Xcode 5 on/, OS X command line tools do not include gcc
-        # anymore. Use clang.
-        if test -z "$$1"
-        then
-            FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL([$1], [clang], [clang])
-        fi
-        if test -z "$$1"
-        then
-            AC_MSG_ERROR([cannot find $3 nor clang in your PATH])
-        fi
+        $1=$BootstrapTmpCmd
     fi
     fi
-    AC_SUBST($1)
 ])
 
 ])
 
+
 AC_DEFUN([MAYBE_OVERRIDE_STAGE0],[
   if test ! -z "$With_$1" -a "$CrossCompiling" != "YES"; then
       AC_MSG_NOTICE([Not cross-compiling, so --with-$1 also sets $2])
 AC_DEFUN([MAYBE_OVERRIDE_STAGE0],[
   if test ! -z "$With_$1" -a "$CrossCompiling" != "YES"; then
       AC_MSG_NOTICE([Not cross-compiling, so --with-$1 also sets $2])
@@ -2139,14 +2107,14 @@ AC_DEFUN([MAYBE_OVERRIDE_STAGE0],[
 # sets CPP command and its arguments
 #
 # $1 = the variable to set to CPP command
 # sets CPP command and its arguments
 #
 # $1 = the variable to set to CPP command
-# $2 = the varibale to set to CPP command arguments
+# $2 = the variable to set to CPP command arguments
 
 AC_DEFUN([FP_CPP_CMD_WITH_ARGS],[
 dnl ** what cpp to use?
 dnl --------------------------------------------------------------
 AC_ARG_WITH(hs-cpp,
 [AC_HELP_STRING([--with-hs-cpp=ARG],
 
 AC_DEFUN([FP_CPP_CMD_WITH_ARGS],[
 dnl ** what cpp to use?
 dnl --------------------------------------------------------------
 AC_ARG_WITH(hs-cpp,
 [AC_HELP_STRING([--with-hs-cpp=ARG],
-        [Use ARG as the path to cpp [default=autodetect]])],
+      [Path to the (C) preprocessor for Haskell files [default=autodetect]])],
 [
     if test "$HostOS" = "mingw32"
     then
 [
     if test "$HostOS" = "mingw32"
     then
@@ -2157,13 +2125,15 @@ AC_ARG_WITH(hs-cpp,
 ],
 [
 
 ],
 [
 
-    HS_CPP_CMD=$WhatGccIsCalled
+    # We can't use $CPP here, since HS_CPP_CMD is expected to be a single
+    # command (no flags), and AC_PROG_CPP defines CPP as "/usr/bin/gcc -E".
+    HS_CPP_CMD=$CC
 
     SOLARIS_GCC_CPP_BROKEN=NO
     SOLARIS_FOUND_GOOD_CPP=NO
     case $host in
         i386-*-solaris2)
 
     SOLARIS_GCC_CPP_BROKEN=NO
     SOLARIS_FOUND_GOOD_CPP=NO
     case $host in
         i386-*-solaris2)
-        GCC_MAJOR_MINOR=`$WhatGccIsCalled --version|grep "gcc (GCC)"|cut -d ' ' -f 3-3|cut -d '.' -f 1-2`
+        GCC_MAJOR_MINOR=`$CC --version|grep "gcc (GCC)"|cut -d ' ' -f 3-3|cut -d '.' -f 1-2`
         if test "$GCC_MAJOR_MINOR" != "3.4"; then
           # this is not 3.4.x release so with broken CPP
           SOLARIS_GCC_CPP_BROKEN=YES
         if test "$GCC_MAJOR_MINOR" != "3.4"; then
           # this is not 3.4.x release so with broken CPP
           SOLARIS_GCC_CPP_BROKEN=YES
@@ -2198,7 +2168,7 @@ dnl ** what cpp flags to use?
 dnl -----------------------------------------------------------
 AC_ARG_WITH(hs-cpp-flags,
   [AC_HELP_STRING([--with-hs-cpp-flags=ARG],
 dnl -----------------------------------------------------------
 AC_ARG_WITH(hs-cpp-flags,
   [AC_HELP_STRING([--with-hs-cpp-flags=ARG],
-          [Use ARG as the path to hs cpp [default=autodetect]])],
+      [Flags to the (C) preprocessor for Haskell files [default=autodetect]])],
   [
       if test "$HostOS" = "mingw32"
       then
   [
       if test "$HostOS" = "mingw32"
       then
@@ -2210,11 +2180,11 @@ AC_ARG_WITH(hs-cpp-flags,
 [
   $HS_CPP_CMD -x c /dev/null -dM -E > conftest.txt 2>&1
   if grep "__clang__" conftest.txt >/dev/null 2>&1; then
 [
   $HS_CPP_CMD -x c /dev/null -dM -E > conftest.txt 2>&1
   if grep "__clang__" conftest.txt >/dev/null 2>&1; then
-    HS_CPP_ARGS="-E -undef -traditional -Wno-invalid-pp-token -Wno-unicode -Wno-trigraphs "
+    HS_CPP_ARGS="-E -undef -traditional -Wno-invalid-pp-token -Wno-unicode -Wno-trigraphs"
   else
       $HS_CPP_CMD  -v > conftest.txt 2>&1
       if  grep "gcc" conftest.txt >/dev/null 2>&1; then
   else
       $HS_CPP_CMD  -v > conftest.txt 2>&1
       if  grep "gcc" conftest.txt >/dev/null 2>&1; then
-          HS_CPP_ARGS="-E -undef -traditional "
+          HS_CPP_ARGS="-E -undef -traditional"
         else
           $HS_CPP_CMD  --version > conftest.txt 2>&1
           if grep "cpphs" conftest.txt >/dev/null 2>&1; then
         else
           $HS_CPP_CMD  --version > conftest.txt 2>&1
           if grep "cpphs" conftest.txt >/dev/null 2>&1; then
@@ -2277,9 +2247,70 @@ AC_DEFUN([FP_BFD_SUPPORT], [
                         [],dnl bfd seems to work
                         [AC_MSG_ERROR([can't use 'bfd' library])])
             LIBS="$save_LIBS"
                         [],dnl bfd seems to work
                         [AC_MSG_ERROR([can't use 'bfd' library])])
             LIBS="$save_LIBS"
-        ],
-        []
+        ]
     )
 ])
 
     )
 ])
 
+
+# FP_CC_LINKER_FLAG_TRY()
+# --------------------
+# Try a particular linker to see whether we can use it. In particular, determine
+# whether we can convince gcc to use it via a -fuse-ld=... flag.
+#
+# $1 = the name of the linker to try
+# $2 = the variable to set with the appropriate GHC flag if the linker is
+# found to be usable
+AC_DEFUN([FP_CC_LINKER_FLAG_TRY], [
+    AC_MSG_CHECKING([whether C compiler supports -fuse-ld=$1])
+    echo 'int main(void) {return 0;}' > conftest.c
+    if $CC -o conftest.o -fuse-ld=$1 conftest.c > /dev/null 2>&1
+    then
+        $2="-fuse-ld=$1"
+        AC_MSG_RESULT([yes])
+    else
+        AC_MSG_RESULT([no])
+    fi
+    rm -f conftest.c conftest.o
+])
+
+# FIND_LD
+# ---------
+# Find the version of `ld` to use and figure out how to get gcc to use it for
+# linking (if --enable-ld-override is enabled). This is used in both in the top
+# level configure.ac and in distrib/configure.ac.in.
+#
+# $1 = the platform
+# $2 = the variable to set with GHC options to configure gcc to use the chosen linker
+#
+AC_DEFUN([FIND_LD],[
+    AC_ARG_ENABLE(ld-override,
+      [AC_HELP_STRING([--disable-ld-override],
+        [Prevent GHC from overriding the default linker used by gcc. If ld-override is enabled GHC will try to tell gcc to use whichever linker is selected by the LD environment variable. [default=override enabled]])],
+      [],
+      [enable_ld_override=yes])
+
+    if test "x$enable_ld_override" = "xyes"; then
+        TmpLd="$LD" # In case the user set LD
+        AC_CHECK_TARGET_TOOLS([TmpLd], [ld.lld ld.gold ld])
+
+        out=`$TmpLd --version`
+        case $out in
+          "GNU ld"*)   FP_CC_LINKER_FLAG_TRY(bfd, $2) ;;
+          "GNU gold"*) FP_CC_LINKER_FLAG_TRY(gold, $2) ;;
+          "LLD"*)      FP_CC_LINKER_FLAG_TRY(lld, $2) ;;
+          *) AC_MSG_NOTICE([unknown linker version $out]) ;;
+        esac
+        if test "z$$2" = "z"; then
+            AC_MSG_NOTICE([unable to convince '$CC' to use linker '$TmpLd'])
+            AC_CHECK_TARGET_TOOL([LD], [ld])
+        else
+            LD="$TmpLd"
+        fi
+   else
+        AC_CHECK_TARGET_TOOL([LD], [ld])
+   fi
+
+   CHECK_LD_COPY_BUG([$1])
+])
+
 # LocalWords:  fi
 # LocalWords:  fi