rts: Fix ASSERTs with space before opening paren
[ghc.git] / aclocal.m4
index 45c94f7..11606c7 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
         ;;
-    *-unknown-mingw32)
+    # examples: i386-unknown-mingw32, i686-w64-mingw32, x86_64-w64-mingw32
+    *-mingw32)
         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-*)
         $3='.dylib'
         ;;
     esac
@@ -141,9 +136,13 @@ AC_DEFUN([FPTOOLS_SET_PLATFORM_VARS],
     TargetVendor_CPP=`  echo "$TargetVendor"   | sed -e 's/\./_/g' -e 's/-/_/g'`
     TargetOS_CPP=`      echo "$TargetOS"       | sed -e 's/\./_/g' -e 's/-/_/g'`
 
+    # 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 "LLVM target: $target"
 
     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(LLVMTarget_CPP)
 
     AC_SUBST(HostVendor_CPP)
     AC_SUBST(BuildVendor_CPP)
@@ -227,11 +227,10 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
 
     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 [$]1])
             ;;
         esac
     }
@@ -271,13 +270,10 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
         haiku)
             test -z "[$]2" || eval "[$]2=OSHaiku"
             ;;
-        osf3)
-            test -z "[$]2" || eval "[$]2=OSOsf3"
-            ;;
         nto-qnx)
             test -z "[$]2" || eval "[$]2=OSQNXNTO"
             ;;
-        dragonfly|osf1|hpux|linuxaout|freebsd2|gnu|nextstep2|nextstep3|sunos4|ultrix|irix)
+        dragonfly|hpux|linuxaout|freebsd2|gnu|nextstep2|nextstep3|sunos4|ultrix)
             test -z "[$]2" || eval "[$]2=OSUnknown"
             ;;
         aix)
@@ -325,9 +321,18 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
     dnl so we empty CFLAGS while running this test
     CFLAGS2="$CFLAGS"
     CFLAGS=
+    case $TargetArch in
+      arm)
+        dnl See #13937.
+        progbits="%progbits"
+        ;;
+      *)
+        progbits="@progbits"
+        ;;
+    esac
     AC_MSG_CHECKING(for GNU non-executable stack support)
     AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM([__asm__ (".section .note.GNU-stack,\"\",@progbits");], [0])],
+        [AC_LANG_PROGRAM([__asm__ (".section .note.GNU-stack,\"\",$progbits");], [0])],
         [AC_MSG_RESULT(yes)
          HaskellHaveGnuNonexecStack=True],
         [AC_MSG_RESULT(no)
@@ -392,6 +397,8 @@ AC_DEFUN([GET_ARM_ISA],
                          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
@@ -451,6 +458,8 @@ AC_DEFUN([GET_ARM_ISA],
                     [ARM_ABI="SOFTFP"]
                )]
         )
+
+        AC_SUBST(ARM_ISA)
 ])
 
 
@@ -459,7 +468,7 @@ AC_DEFUN([GET_ARM_ISA],
 # 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"
@@ -471,17 +480,44 @@ AC_DEFUN([FP_SETTINGS],
         SettingsDllWrapCommand="\$topdir/../${mingw_bin_prefix}dllwrap.exe"
         SettingsWindresCommand="\$topdir/../${mingw_bin_prefix}windres.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
-        SettingsCCompilerCommand="$WhatGccIsCalled"
+        SettingsCCompilerCommand="$CC"
         SettingsHaskellCPPCommand="$HaskellCPPCmd"
         SettingsHaskellCPPFlags="$HaskellCPPArgs"
         SettingsLdCommand="$LdCmd"
         SettingsArCommand="$ArCmd"
         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="$LibtoolCmd"
     fi
     if test -z "$LlcCmd"
     then
@@ -497,12 +533,14 @@ AC_DEFUN([FP_SETTINGS],
     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)
+    AC_SUBST(SettingsCCompilerSupportsNoPie)
     AC_SUBST(SettingsLdCommand)
     AC_SUBST(SettingsLdFlags)
     AC_SUBST(SettingsArCommand)
@@ -515,10 +553,52 @@ AC_DEFUN([FP_SETTINGS],
     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
 # ----------------------------------
-# 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
@@ -541,18 +621,6 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
     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="$$3 -m64"
@@ -576,34 +644,32 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
         ;;
     arm*linux*)
         # On arm/linux and arm/android, tell gcc to generate Arm
-        # instructions (ie not Thumb) and to link using the gold linker.
-        # Forcing LD to be ld.gold is done in FIND_LD m4 macro.
+        # instructions (ie not Thumb).
         $2="$$2 -marm"
-        $3="$$3 -fuse-ld=gold -Wl,-z,noexecstack"
+        $3="$$3 -Wl,-z,noexecstack"
         $4="$$4 -z noexecstack"
         ;;
 
     aarch64*linux*)
-        # On aarch64/linux and aarch64/android, tell gcc to link using the
-        # gold linker.
-        # Forcing LD to be ld.gold is done in FIND_LD m4 macro.
-        $3="$$3 -fuse-ld=gold -Wl,-z,noexecstack"
+        $3="$$3 -Wl,-z,noexecstack"
         $4="$$4 -z noexecstack"
         ;;
 
     powerpc-ibm-aix*)
-        # On IBM AIX, we need to workaround XCOFF's limitations. Specifically,
-        # there's a TOC which only supports at most 16k entries (see
-        # http://www.ibm.com/developerworks/rational/library/overview-toc-aix/
-        # for more details), and by using `-mminimal-toc` we use up only one TOC
-        # entry per translation unit, at the cost of an additional pointer
-        # indirection. However, see note in `compiler/ghc.mk` about `Parser.hs`.
-        # Finally, we need `-D_THREAD_SAFE` to unlock a thread-local `errno`.
-        $2="$$2 -mminimal-toc -D_THREAD_SAFE"
-        $3="$$3 -mminimal-toc -D_THREAD_SAFE"
+        # 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.
@@ -664,75 +730,6 @@ 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.
@@ -795,6 +792,16 @@ m4_popdef([fp_Cache])[]dnl
 ])# 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
@@ -806,26 +813,24 @@ m4_popdef([fp_Cache])[]dnl
 # 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?!?
-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;;
-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}};
@@ -989,15 +994,14 @@ AC_SUBST([LdHasBuildId])
 # -----------------
 # 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],
-[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
-  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
 
 
@@ -1062,7 +1066,9 @@ AC_SUBST([LdHasFilelist])
 # ----------
 # Sets fp_prog_ar to a path to ar. Exits if no ar can be found
 AC_DEFUN([FP_PROG_AR],
-[AC_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
@@ -1160,7 +1166,7 @@ AC_DEFUN([FP_PROG_AR_NEEDS_RANLIB],[
     if test $fp_prog_ar_is_gnu = yes
     then
         fp_cv_prog_ar_needs_ranlib=no
-    elif test "$TargetOS_CPP" = "darwin"
+    elif test "$TargetVendor_CPP" = "apple"
     then
         # It's quite tedious to check for Apple's crazy timestamps in
         # .a files, so we hardcode it.
@@ -1207,6 +1213,7 @@ then
   AC_MSG_ERROR([gcc is required])
 fi
 GccLT34=NO
+GccLT44=NO
 GccLT46=NO
 AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
 [
@@ -1217,10 +1224,12 @@ AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
     # isn't a very good reason for that, but for now just make configure
     # fail.
     FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [3.4], GccLT34=YES)
+    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)
+AC_SUBST(GccLT44)
 AC_SUBST(GccLT46)
 ])# FP_GCC_VERSION
 
@@ -1254,6 +1263,26 @@ AC_SUBST(GccIsClang)
 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 $CC -no-pie -x c /dev/null -dM -E > conftest.txt 2>&1 && ! grep -i unrecognized conftest.txt > /dev/null 2>&1; then
+       CONF_GCC_SUPPORTS_NO_PIE=YES
+       AC_MSG_RESULT([yes])
+   else
+       CONF_GCC_SUPPORTS_NO_PIE=NO
+       AC_MSG_RESULT([no])
+   fi
+   rm -f conftest.c conftest.o conftest
+])
+
 dnl Small feature test for perl version. Assumes PerlCmd
 dnl contains path to perl binary.
 dnl
@@ -1458,10 +1487,11 @@ if test "$RELEASE" = "NO"; then
         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
-                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)
@@ -1532,8 +1562,22 @@ AC_SUBST([ProjectPatchLevel2])
 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
@@ -1704,11 +1748,6 @@ AC_DEFUN([FP_CURSES],
   dnl * Deal with arguments telling us curses is somewhere odd
   dnl--------------------------------------------------------------------
 
-  AC_ARG_WITH([curses-includes],
-    [AC_HELP_STRING([--with-curses-includes],
-      [directory containing curses headers])],
-      [CURSES_INCLUDE_DIRS=$withval])
-
   AC_ARG_WITH([curses-libraries],
     [AC_HELP_STRING([--with-curses-libraries],
       [directory containing curses libraries])],
@@ -1722,33 +1761,17 @@ AC_DEFUN([FP_CURSES],
 # Calculate absolute path to build tree
 # --------------------------------------------------------------
 
-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
-
-    GHC_PWD=utils/ghc-pwd/dist-boot/ghc-pwd
-])
-
-AC_DEFUN([FP_BINDIST_GHC_PWD],[
-    GHC_PWD=utils/ghc-pwd/dist-install/build/tmp/ghc-pwd-bindist
-])
-
 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/|/|'`
@@ -1875,12 +1898,11 @@ AC_DEFUN([GHC_CONVERT_VENDOR],[
 # --------------------------------
 # converts os from gnu to ghc naming, and assigns the result to $target_var
 AC_DEFUN([GHC_CONVERT_OS],[
-case "$1-$2" in
-  darwin10-arm|darwin11-i386|darwin14-aarch64)
-    $3="ios"
-    ;;
-  *)
     case "$1" in
+      # watchos and tvos are ios variants as of May 2017.
+      ios|watchos|tvos)
+        $3="ios"
+        ;;
       linux-android*)
         $3="linux-android"
         ;;
@@ -1888,12 +1910,15 @@ case "$1-$2" in
         $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|mingw32|darwin|gnu|nextstep2|nextstep3|sunos4|ultrix|irix|haiku)
+      freebsd|netbsd|openbsd|dragonfly|hpux|linuxaout|kfreebsdgnu|freebsd2|solaris2|mingw32|darwin|gnu|nextstep2|nextstep3|sunos4|ultrix|haiku)
         $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
@@ -1907,8 +1932,6 @@ case "$1-$2" in
         exit 1
         ;;
       esac
-      ;;
-  esac
 ])
 
 # BOOTSTRAPPING_GHC_INFO_FIELD
@@ -1940,7 +1963,7 @@ AC_SUBST(LIBRARY_[]translit([$1], [-], [_])[]_VERSION)
 # --------------------------------
 # Gets the version number of XCode, if on a Mac
 AC_DEFUN([XCODE_VERSION],[
-    if test "$TargetOS_CPP" = "darwin"
+    if test "$TargetVendor_CPP" = "apple"
     then
         AC_MSG_CHECKING(XCode version)
         XCodeVersion=`xcodebuild -version | grep Xcode | sed "s/Xcode //"`
@@ -1968,49 +1991,80 @@ AC_DEFUN([XCODE_VERSION],[
 # 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
-# $4 = the version of 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],[
-    # Test for program with version name.
-    FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL_NOTARGET([$1], [$2], [$3-$4])
-    if test -z "$$1"; then
-        # Test for program without version name.
-        FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL_NOTARGET([$1], [$2], [$3])
-        if test -n "$$1"; then
-            AC_MSG_CHECKING([$$1 is version $4])
-            if test `$$1 --version | grep -c "version $4"` -gt 0 ; then
-                AC_MSG_RESULT(yes)
-            else
-                AC_MSG_RESULT(no)
-                $1=""
-            fi
+    # 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
 ])
 
-# FIND_LD
-# Find the version of `ld` to use. This is used in both in the top level
-# configure.ac and in distrib/configure.ac.in.
+# 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 variable to set
+# $1 = the platform
 #
-AC_DEFUN([FIND_LD],[
-    FP_ARG_WITH_PATH_GNU_PROG([LD], [ld], [ld])
-    case $target in
-        arm*linux*       | \
-        aarch64*linux*   )
-            # Arm and Aarch64 requires use of the binutils ld.gold linker.
-            # This case should catch at least arm-unknown-linux-gnueabihf,
-            # arm-linux-androideabi, arm64-unknown-linux and
-            # aarch64-linux-android
-            FP_ARG_WITH_PATH_GNU_PROG([LD_GOLD], [ld.gold], [ld.gold])
-            $1="$LD_GOLD"
-            ;;
-        *)
-            $1="$LD"
-            ;;
+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
 ])
 
@@ -2033,41 +2087,6 @@ AC_DEFUN([FIND_GHC_BOOTSTRAP_PROG],[
 ])
 
 
-# FIND_GCC()
-# --------------------------------
-# Finds where gcc is
-#
-# $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"
-    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
-    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])
@@ -2081,7 +2100,7 @@ AC_DEFUN([MAYBE_OVERRIDE_STAGE0],[
 # 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?
@@ -2101,13 +2120,13 @@ AC_ARG_WITH(hs-cpp,
 
     # We can't use $CPP here, since HS_CPP_CMD is expected to be a single
     # command (no flags), and AC_PROG_CPP defines CPP as "/usr/bin/gcc -E".
-    HS_CPP_CMD=$WhatGccIsCalled
+    HS_CPP_CMD=$CC
 
     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
@@ -2225,4 +2244,66 @@ AC_DEFUN([FP_BFD_SUPPORT], [
     )
 ])
 
+
+# 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