configure.ac

target_configargs="$target_configargs ${tbaseargs}"

# Passing a --with-cross-host argument lets the target libraries know
# whether they are being built with a cross-compiler or being built
# native.  However, it would be better to use other mechanisms to make the
# sorts of decisions they want to make on this basis.  Please consider
# this option to be deprecated.  FIXME.
if test x${is_cross_compiler} = xyes ; then
  target_configargs="--with-cross-host=${host_noncanonical} ${target_configargs}"
fi

# Special user-friendly check for native x86_64-linux build, if
# multilib is not explicitly enabled.
case "$target:$have_compiler:$host:$target:$enable_multilib" in
  x86_64-*linux*:yes:$build:$build:)
    # Make sure we have a developement environment that handles 32-bit
    dev64=no
    echo "int main () { return 0; }" > conftest.c
    ${CC} -m32 -o conftest ${CFLAGS} ${CPPFLAGS} ${LDFLAGS} conftest.c
    if test $? = 0 ; then
      if test -s conftest || test -s conftest.exe ; then
	dev64=yes
      fi
    fi 
    rm -f conftest*
    if test x${dev64} != xyes ; then
      AC_MSG_ERROR([I suspect your system does not have 32-bit developement libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib.])
    fi
    ;;
esac

# Default to --enable-multilib.
if test x${enable_multilib} = x ; then
  target_configargs="--enable-multilib ${target_configargs}"
fi

# Pass --with-newlib if appropriate.  Note that target_configdirs has
# changed from the earlier setting of with_newlib.
if test x${with_newlib} != xno && echo " ${target_configdirs} " | grep " newlib " > /dev/null 2>&1 && test -d ${srcdir}/newlib ; then
  target_configargs="--with-newlib ${target_configargs}"
fi

# Different target subdirs use different values of certain variables
# (notably CXX).  Worse, multilibs use *lots* of different values.
# Worse yet, autoconf 2.5x makes some of these 'precious', meaning that
# it doesn't automatically accept command-line overrides of them.
# This means it's not safe for target subdirs to share a cache file,
# which is disgusting, but there you have it.  Hopefully this can be
# fixed in future.  It's still worthwhile to use a cache file for each
# directory.  I think.

# Pass the appropriate --build, --host, --target and --cache-file arguments.
# We need to pass --target, as newer autoconf's requires consistency
# for target_alias and gcc doesn't manage it consistently.
target_configargs="--cache-file=./config.cache ${target_configargs}"

FLAGS_FOR_TARGET=
case " $target_configdirs " in
 *" newlib "*)
  case " $target_configargs " in
  *" --with-newlib "*)
   case "$target" in
    *-cygwin*)
      FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(TARGET_SUBDIR)/winsup/cygwin -isystem $$s/winsup/cygwin/include'
      ;;
   esac

   # If we're not building GCC, don't discard standard headers.
   if test -d ${srcdir}/gcc; then
     FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -nostdinc'

     if test "${build}" != "${host}"; then
       # On Canadian crosses, CC_FOR_TARGET will have already been set
       # by `configure', so we won't have an opportunity to add -Bgcc/
       # to it.  This is right: we don't want to search that directory
       # for binaries, but we want the header files in there, so add
       # them explicitly.
       FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -isystem $$r/$(HOST_SUBDIR)/gcc/include -isystem $$r/$(HOST_SUBDIR)/gcc/include-fixed'

       # Someone might think of using the pre-installed headers on
       # Canadian crosses, in case the installed compiler is not fully
       # compatible with the compiler being built.  In this case, it
       # would be better to flag an error than risking having
       # incompatible object files being constructed.  We can't
       # guarantee that an error will be flagged, but let's hope the
       # compiler will do it, when presented with incompatible header
       # files.
     fi
   fi

   case "${target}-${is_cross_compiler}" in
   i[[3456789]]86-*-linux*-no)
      # Here host == target, so we don't need to build gcc,
      # so we don't want to discard standard headers.
      FLAGS_FOR_TARGET=`echo " $FLAGS_FOR_TARGET " | sed -e 's/ -nostdinc / /'`
      ;;
   *)
      # If we're building newlib, use its generic headers last, but search
      # for any libc-related directories first (so make it the last -B
      # switch).
      FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -B$$r/$(TARGET_SUBDIR)/newlib/ -isystem $$r/$(TARGET_SUBDIR)/newlib/targ-include -isystem $$s/newlib/libc/include'

      # If we're building libgloss, find the startup file, simulator library
      # and linker script.
      case " $target_configdirs " in
	*" libgloss "*)
	# Look for startup file, simulator library and maybe linker script.
	FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -B$$r/$(TARGET_SUBDIR)/libgloss/'"$libgloss_dir"
	# Look for libnosys.a in case the target needs it.
	FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(TARGET_SUBDIR)/libgloss/libnosys'
	# Most targets have the linker script in the source directory.
	FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$s/libgloss/'"$libgloss_dir"
	;;
      esac
      ;;
   esac
   ;;
  esac
  ;;
esac

case "$target" in
  x86_64-*mingw* | *-w64-mingw*)
  # MinGW-w64 does not use newlib, nor does it use winsup. It may,
  # however, use a symlink named 'mingw' in ${prefix} .
    FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L${prefix}/${target}/lib -L${prefix}/mingw/lib -isystem ${prefix}/${target}/include -isystem ${prefix}/mingw/include'
    ;;
  *-mingw*)
  # MinGW can't be handled as Cygwin above since it does not use newlib.
    FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(TARGET_SUBDIR)/winsup/mingw -L$$r/$(TARGET_SUBDIR)/winsup/w32api/lib -isystem $$s/winsup/mingw/include -isystem $$s/winsup/w32api/include'
    ;;
esac

# Allow the user to override the flags for
# our build compiler if desired.
if test x"${build}" = x"${host}" ; then
  CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
  CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CXXFLAGS}}
  LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${LDFLAGS}}
fi

# On Canadian crosses, we'll be searching the right directories for
# the previously-installed cross compiler, so don't bother to add
# flags for directories within the install tree of the compiler
# being built; programs in there won't even run.
if test "${build}" = "${host}" && test -d ${srcdir}/gcc; then
  # Search for pre-installed headers if nothing else fits.
  FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -B$(build_tooldir)/bin/ -B$(build_tooldir)/lib/ -isystem $(build_tooldir)/include -isystem $(build_tooldir)/sys-include'
fi

if test "x${use_gnu_ld}" = x &&
   echo " ${configdirs} " | grep " ld " > /dev/null ; then
  # Arrange for us to find uninstalled linker scripts.
  FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(HOST_SUBDIR)/ld'
fi

# Search for other target-specific linker scripts and such.
case "${target}" in
  mep*)
    FLAGS_FOR_TARGET="$FLAGS_FOR_TARGET -mlibrary"
    ;;
esac

# Makefile fragments.
for frag in host_makefile_frag target_makefile_frag alphaieee_frag ospace_frag;
do
  eval fragval=\$$frag
  if test $fragval != /dev/null; then
    eval $frag=${srcdir}/$fragval
  fi
done
AC_SUBST_FILE(host_makefile_frag)
AC_SUBST_FILE(target_makefile_frag)
AC_SUBST_FILE(alphaieee_frag)
AC_SUBST_FILE(ospace_frag)

# Miscellanea: directories, flags, etc.
AC_SUBST(RPATH_ENVVAR)
AC_SUBST(GCC_SHLIB_SUBDIR)
AC_SUBST(tooldir)
AC_SUBST(build_tooldir)
AC_SUBST(CONFIGURE_GDB_TK)
AC_SUBST(GDB_TK)
AC_SUBST(INSTALL_GDB_TK)

# Build module lists & subconfigure args.
AC_SUBST(build_configargs)
AC_SUBST(build_configdirs)

# Host module lists & subconfigure args.
AC_SUBST(host_configargs)
AC_SUBST(configdirs)
AC_SUBST(target_configdirs)

# Target module lists & subconfigure args.
AC_SUBST(target_configargs)


# Build tools.
AC_SUBST(AR_FOR_BUILD)
AC_SUBST(AS_FOR_BUILD)
AC_SUBST(CC_FOR_BUILD)
AC_SUBST(CFLAGS_FOR_BUILD)
AC_SUBST(CXXFLAGS_FOR_BUILD)
AC_SUBST(CXX_FOR_BUILD)
AC_SUBST(DLLTOOL_FOR_BUILD)
AC_SUBST(GCJ_FOR_BUILD)
AC_SUBST(GFORTRAN_FOR_BUILD)
AC_SUBST(GOC_FOR_BUILD)
AC_SUBST(LDFLAGS_FOR_BUILD)
AC_SUBST(LD_FOR_BUILD)
AC_SUBST(NM_FOR_BUILD)
AC_SUBST(RANLIB_FOR_BUILD)
AC_SUBST(WINDMC_FOR_BUILD)
AC_SUBST(WINDRES_FOR_BUILD)

# Generate default definitions for YACC, M4, LEX and other programs that run
# on the build machine.  These are used if the Makefile can't locate these
# programs in objdir.
MISSING=`cd $ac_aux_dir && ${PWDCMD-pwd}`/missing

AC_CHECK_PROGS([YACC], ['bison -y' byacc yacc], [$MISSING bison -y])
case " $build_configdirs " in
  *" bison "*) YACC='$$r/$(BUILD_SUBDIR)/bison/tests/bison -y' ;;
esac

AC_CHECK_PROGS([BISON], [bison], [$MISSING bison])
case " $build_configdirs " in
  *" bison "*) BISON='$$r/$(BUILD_SUBDIR)/bison/tests/bison' ;;
esac

AC_CHECK_PROGS([M4], [gm4 gnum4 m4], [$MISSING m4])
case " $build_configdirs " in
  *" m4 "*) M4='$$r/$(BUILD_SUBDIR)/m4/m4' ;;
esac

AC_CHECK_PROGS([LEX], [flex lex], [$MISSING flex])
case " $build_configdirs " in
  *" flex "*) LEX='$$r/$(BUILD_SUBDIR)/flex/flex' ;;
  *" lex "*) LEX='$$r/$(BUILD_SUBDIR)/lex/lex' ;;
esac

AC_CHECK_PROGS([FLEX], [flex], [$MISSING flex])
case " $build_configdirs " in
  *" flex "*) FLEX='$$r/$(BUILD_SUBDIR)/flex/flex' ;;
esac

AC_CHECK_PROGS([MAKEINFO], makeinfo, [$MISSING makeinfo])
case " $build_configdirs " in
  *" texinfo "*) MAKEINFO='$$r/$(BUILD_SUBDIR)/texinfo/makeinfo/makeinfo' ;;
  *)
changequote(,)
    # For an installed makeinfo, we require it to be from texinfo 4.7 or
    # higher, else we use the "missing" dummy.
    if ${MAKEINFO} --version \
       | egrep 'texinfo[^0-9]*(4\.([7-9]|[1-9][0-9])|[5-9]|[1-9][0-9])' >/dev/null 2>&1; then
      :
    else
      MAKEINFO="$MISSING makeinfo"
    fi
    ;;
changequote([,])
esac

# FIXME: expect and dejagnu may become build tools?

AC_CHECK_PROGS(EXPECT, expect, expect)
case " $configdirs " in
  *" expect "*)
    test $host = $build && EXPECT='$$r/$(HOST_SUBDIR)/expect/expect'
    ;;
esac

AC_CHECK_PROGS(RUNTEST, runtest, runtest)
case " $configdirs " in
  *" dejagnu "*)
    test $host = $build && RUNTEST='$$s/$(HOST_SUBDIR)/dejagnu/runtest'
    ;;
esac


# Host tools.
NCN_STRICT_CHECK_TOOLS(AR, ar)
NCN_STRICT_CHECK_TOOLS(AS, as)
NCN_STRICT_CHECK_TOOLS(DLLTOOL, dlltool)
NCN_STRICT_CHECK_TOOLS(LD, ld)
NCN_STRICT_CHECK_TOOLS(LIPO, lipo)
NCN_STRICT_CHECK_TOOLS(NM, nm)
NCN_STRICT_CHECK_TOOLS(RANLIB, ranlib, true)
NCN_STRICT_CHECK_TOOLS(STRIP, strip, true)
NCN_STRICT_CHECK_TOOLS(WINDRES, windres)
NCN_STRICT_CHECK_TOOLS(WINDMC, windmc)
NCN_STRICT_CHECK_TOOLS(OBJCOPY, objcopy)
NCN_STRICT_CHECK_TOOLS(OBJDUMP, objdump)
NCN_STRICT_CHECK_TOOLS(READELF, readelf)
AC_SUBST(CC)
AC_SUBST(CXX)
AC_SUBST(CFLAGS)
AC_SUBST(CXXFLAGS)

# Target tools.
AC_ARG_WITH([build-time-tools], 
  [AS_HELP_STRING([--with-build-time-tools=PATH],
		  [use given path to find target tools during the build])],
  [case x"$withval" in
     x/*) ;;
     *)
       with_build_time_tools=
       AC_MSG_WARN([argument to --with-build-time-tools must be an absolute path])
       ;;
   esac],
  [with_build_time_tools=])

NCN_STRICT_CHECK_TARGET_TOOLS(CC_FOR_TARGET, cc gcc)
NCN_STRICT_CHECK_TARGET_TOOLS(CXX_FOR_TARGET, c++ g++ cxx gxx)
NCN_STRICT_CHECK_TARGET_TOOLS(GCC_FOR_TARGET, gcc, ${CC_FOR_TARGET})
NCN_STRICT_CHECK_TARGET_TOOLS(GCJ_FOR_TARGET, gcj)
NCN_STRICT_CHECK_TARGET_TOOLS(GFORTRAN_FOR_TARGET, gfortran)
NCN_STRICT_CHECK_TARGET_TOOLS(GOC_FOR_TARGET, gccgo)

ACX_CHECK_INSTALLED_TARGET_TOOL(AR_FOR_TARGET, ar)
ACX_CHECK_INSTALLED_TARGET_TOOL(AS_FOR_TARGET, as)
ACX_CHECK_INSTALLED_TARGET_TOOL(DLLTOOL_FOR_TARGET, dlltool)
ACX_CHECK_INSTALLED_TARGET_TOOL(LD_FOR_TARGET, ld)
ACX_CHECK_INSTALLED_TARGET_TOOL(LIPO_FOR_TARGET, lipo)
ACX_CHECK_INSTALLED_TARGET_TOOL(NM_FOR_TARGET, nm)
ACX_CHECK_INSTALLED_TARGET_TOOL(OBJCOPY_FOR_TARGET, objcopy)
ACX_CHECK_INSTALLED_TARGET_TOOL(OBJDUMP_FOR_TARGET, objdump)
ACX_CHECK_INSTALLED_TARGET_TOOL(RANLIB_FOR_TARGET, ranlib)
ACX_CHECK_INSTALLED_TARGET_TOOL(READELF_FOR_TARGET, readelf)
ACX_CHECK_INSTALLED_TARGET_TOOL(STRIP_FOR_TARGET, strip)
ACX_CHECK_INSTALLED_TARGET_TOOL(WINDRES_FOR_TARGET, windres)
ACX_CHECK_INSTALLED_TARGET_TOOL(WINDMC_FOR_TARGET, windmc)

RAW_CXX_FOR_TARGET="$CXX_FOR_TARGET"

GCC_TARGET_TOOL(ar, AR_FOR_TARGET, AR, [binutils/ar])
GCC_TARGET_TOOL(as, AS_FOR_TARGET, AS, [gas/as-new])
GCC_TARGET_TOOL(cc, CC_FOR_TARGET, CC, [gcc/xgcc -B$$r/$(HOST_SUBDIR)/gcc/])
dnl see comments for CXX_FOR_TARGET_FLAG_TO_PASS
GCC_TARGET_TOOL(c++, CXX_FOR_TARGET, CXX,
		[gcc/xg++ -B$$r/$(HOST_SUBDIR)/gcc/ -nostdinc++ `if test -f $$r/$(TARGET_SUBDIR)/libstdc++-v3/scripts/testsuite_flags; then $(SHELL) $$r/$(TARGET_SUBDIR)/libstdc++-v3/scripts/testsuite_flags --build-includes; else echo -funconfigured-libstdc++-v3 ; fi` -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src/.libs -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/libsupc++/.libs],
		c++)
GCC_TARGET_TOOL(c++ for libstdc++, RAW_CXX_FOR_TARGET, CXX,
		[gcc/xgcc -shared-libgcc -B$$r/$(HOST_SUBDIR)/gcc -nostdinc++ -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src/.libs -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/libsupc++/.libs],
		c++)
GCC_TARGET_TOOL(dlltool, DLLTOOL_FOR_TARGET, DLLTOOL, [binutils/dlltool])
GCC_TARGET_TOOL(gcc, GCC_FOR_TARGET, , [gcc/xgcc -B$$r/$(HOST_SUBDIR)/gcc/])
GCC_TARGET_TOOL(gcj, GCJ_FOR_TARGET, GCJ,
		[gcc/gcj -B$$r/$(HOST_SUBDIR)/gcc/], java)
GCC_TARGET_TOOL(gfortran, GFORTRAN_FOR_TARGET, GFORTRAN,
		[gcc/gfortran -B$$r/$(HOST_SUBDIR)/gcc/], fortran)
GCC_TARGET_TOOL(gccgo, GOC_FOR_TARGET, GOC,
		[gcc/gccgo -B$$r/$(HOST_SUBDIR)/gcc/], go)
GCC_TARGET_TOOL(ld, LD_FOR_TARGET, LD, [ld/ld-new])
GCC_TARGET_TOOL(lipo, LIPO_FOR_TARGET, LIPO)
GCC_TARGET_TOOL(nm, NM_FOR_TARGET, NM, [binutils/nm-new])
GCC_TARGET_TOOL(objcopy, OBJCOPY_FOR_TARGET, OBJDUMP, [binutils/objcopy])
GCC_TARGET_TOOL(objdump, OBJDUMP_FOR_TARGET, OBJDUMP, [binutils/objdump])
GCC_TARGET_TOOL(ranlib, RANLIB_FOR_TARGET, RANLIB, [binutils/ranlib])
GCC_TARGET_TOOL(readelf, READELF_FOR_TARGET, READELF, [binutils/readelf])
GCC_TARGET_TOOL(strip, STRIP_FOR_TARGET, STRIP, [binutils/strip-new])
GCC_TARGET_TOOL(windres, WINDRES_FOR_TARGET, WINDRES, [binutils/windres])
GCC_TARGET_TOOL(windmc, WINDMC_FOR_TARGET, WINDMC, [binutils/windmc])

AC_SUBST(FLAGS_FOR_TARGET)
AC_SUBST(RAW_CXX_FOR_TARGET)

# Certain tools may need extra flags.
AR_FOR_TARGET=${AR_FOR_TARGET}${extra_arflags_for_target}
RANLIB_FOR_TARGET=${RANLIB_FOR_TARGET}${extra_ranlibflags_for_target}
NM_FOR_TARGET=${NM_FOR_TARGET}${extra_nmflags_for_target}

# When building target libraries, except in a Canadian cross, we use
# the same toolchain as the compiler we just built.
COMPILER_AS_FOR_TARGET='$(AS_FOR_TARGET)'
COMPILER_LD_FOR_TARGET='$(LD_FOR_TARGET)'
COMPILER_NM_FOR_TARGET='$(NM_FOR_TARGET)'
if test $host = $build; then
  case " $configdirs " in
    *" gcc "*)
      COMPILER_AS_FOR_TARGET='$$r/$(HOST_SUBDIR)/gcc/as'
      COMPILER_LD_FOR_TARGET='$$r/$(HOST_SUBDIR)/gcc/collect-ld'
      COMPILER_NM_FOR_TARGET='$$r/$(HOST_SUBDIR)/gcc/nm'${extra_nmflags_for_target}
      ;;
  esac
fi

AC_SUBST(COMPILER_AS_FOR_TARGET)
AC_SUBST(COMPILER_LD_FOR_TARGET)
AC_SUBST(COMPILER_NM_FOR_TARGET)

AC_MSG_CHECKING([whether to enable maintainer-specific portions of Makefiles])
AC_ARG_ENABLE(maintainer-mode,
[AS_HELP_STRING([--enable-maintainer-mode],
		[enable make rules and dependencies not useful
		 (and sometimes confusing) to the casual installer])],
      USE_MAINTAINER_MODE=$enableval,
      USE_MAINTAINER_MODE=no)
AC_MSG_RESULT($USE_MAINTAINER_MODE)
AC_SUBST(MAINTAINER_MODE_TRUE)
AC_SUBST(MAINTAINER_MODE_FALSE)
if test "$USE_MAINTAINER_MODE" = yes; then
  MAINTAINER_MODE_TRUE=
  MAINTAINER_MODE_FALSE='#'
else
  MAINTAINER_MODE_TRUE='#'
  MAINTAINER_MODE_FALSE=
fi	
MAINT=$MAINTAINER_MODE_TRUE
AC_SUBST(MAINT)dnl

# ---------------------
# GCC bootstrap support
# ---------------------

# Stage specific cflags for build.
stage1_cflags="-g"
case $build in
  vax-*-*)
    case ${GCC} in
      yes) stage1_cflags="-g -Wa,-J" ;;
      *) stage1_cflags="-g -J" ;;
    esac ;;
esac

AC_SUBST(stage1_cflags)

# Enable --enable-checking in stage1 of the compiler.
AC_ARG_ENABLE(stage1-checking,
[AS_HELP_STRING([[--enable-stage1-checking[=all]]],
		[choose additional checking for stage1 of the compiler])],
[stage1_checking=--enable-checking=${enable_stage1_checking}],
[if test "x$enable_checking" = xno || test "x$enable_checking" = x; then
  stage1_checking=--enable-checking=yes,types
else
  stage1_checking=--enable-checking=$enable_checking,types
fi])
AC_SUBST(stage1_checking)

# Enable -Werror in bootstrap stage2 and later.
AC_ARG_ENABLE(werror,
[AS_HELP_STRING([--enable-werror],
		[enable -Werror in bootstrap stage2 and later])], [],
[if test -d ${srcdir}/gcc && test x"`cat $srcdir/gcc/DEV-PHASE`" = xexperimental; then
  enable_werror=yes
else
  enable_werror=no
fi])
case ${enable_werror} in
  yes) stage2_werror_flag="--enable-werror-always" ;;
  *) stage2_werror_flag="" ;;
esac
AC_SUBST(stage2_werror_flag)

# Enable --enable-host-shared.
AC_ARG_ENABLE(host-shared,
[AS_HELP_STRING([--enable-host-shared],
		[build host code as shared libraries])],
[host_shared=$enableval], [host_shared=no])
AC_SUBST(host_shared)

# Specify what files to not compare during bootstrap.

compare_exclusions="gcc/cc*-checksum\$(objext) | gcc/ada/*tools/*"
case "$target" in
  hppa*64*-*-hpux*) ;;
  hppa*-*-hpux*) compare_exclusions="gcc/cc*-checksum\$(objext) | */libgcc/lib2funcs* | gcc/ada/*tools/*" ;;
  powerpc*-ibm-aix*) compare_exclusions="gcc/cc*-checksum\$(objext) | gcc/ada/*tools/* | *libgomp*\$(objext)" ;;
esac
AC_SUBST(compare_exclusions)

AC_CONFIG_FILES([Makefile],
  [sed "$extrasub_build" Makefile |
   sed "$extrasub_host" |
   sed "$extrasub_target" > mf$$
   mv -f mf$$ Makefile],
  [extrasub_build="$extrasub_build"
   extrasub_host="$extrasub_host"
   extrasub_target="$extrasub_target"])
AC_OUTPUT