autoconf/configure.ac

dnl Initialize autoconf
AC_INIT([[LLVM]],[[1.4]],[llvmbugs@cs.uiuc.edu])

dnl Place all of the extra autoconf files into the config subdirectory
AC_CONFIG_AUX_DIR([autoconf])

dnl Quit if the source directory has already been configured.
dnl NOTE: This relies upon undocumented autoconf behavior.
if test ${srcdir} != "."
then
	if test -f ${srcdir}/include/Config/config.h
	then
		AC_MSG_ERROR([Already configured in ${srcdir}])
	fi
fi

dnl Configure all of the projects present in our source tree.
for i in `ls ${srcdir}/projects`
do
  if test ${i} != "CVS"
  then
    if test -f ${srcdir}/projects/${i}/configure
    then
      AC_CONFIG_SUBDIRS(projects/${i})
    fi
  fi
done

dnl Configure header files
AC_CONFIG_HEADERS(include/Config/config.h)

dnl Configure other output file
AC_CONFIG_FILES(Makefile.config
 include/Support/DataTypes.h
 include/Support/ThreadSupport.h
 include/Support/hash_map
 include/Support/hash_set
 include/Support/iterator)

dnl Do special configuration of Makefiles
AC_CONFIG_MAKEFILE(Makefile)
AC_CONFIG_MAKEFILE(Makefile.common)
AC_CONFIG_MAKEFILE(examples/Makefile)
AC_CONFIG_MAKEFILE(lib/Makefile)
AC_CONFIG_MAKEFILE(runtime/Makefile)
AC_CONFIG_MAKEFILE(test/Makefile)
AC_CONFIG_MAKEFILE(test/Makefile.tests)
AC_CONFIG_MAKEFILE(test/QMTest/llvm.py)
AC_CONFIG_MAKEFILE(test/QMTest/llvmdb.py)
AC_CONFIG_MAKEFILE(test/Programs/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/Makefile.programs)
AC_CONFIG_MAKEFILE(test/Programs/Makefile.tests)
AC_CONFIG_MAKEFILE(test/Programs/TEST.aa.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.dsgraph.report)
AC_CONFIG_MAKEFILE(test/Programs/TEST.aa.report)
AC_CONFIG_MAKEFILE(test/Programs/TEST.example.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.nightly.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.buildrepo.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.jit.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.nightly.report)
AC_CONFIG_MAKEFILE(test/Programs/TEST.dsgraph.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.jit.report)
AC_CONFIG_MAKEFILE(test/Programs/TEST.typesafe.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/TEST.dsgraph.gnuplot)
AC_CONFIG_MAKEFILE(test/Programs/TEST.vtl.Makefile)
AC_CONFIG_MAKEFILE(test/Programs/External/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/External/SPEC/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/External/SPEC/Makefile.spec)
AC_CONFIG_MAKEFILE(test/Programs/External/SPEC/Makefile.spec2000)
AC_CONFIG_MAKEFILE(test/Programs/External/SPEC/Makefile.spec95)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Makefile.multisrc)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/analyzer/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/distray/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/distray/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/fourinarow/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/fourinarow/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/mason/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/mason/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/neural/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/neural/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/pcompress2/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/pcompress2/test.in)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/pifft/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/MultiSource/Benchmarks/FreeBench/pifft/test.in)
AC_CONFIG_MAKEFILE(test/Programs/SingleSource/Makefile)
AC_CONFIG_MAKEFILE(test/Programs/SingleSource/Makefile.singlesrc)
AC_CONFIG_MAKEFILE(test/Programs/SingleSource/UnitTests/SetjmpLongjmp/Makefile)
AC_CONFIG_MAKEFILE(tools/Makefile)
AC_CONFIG_MAKEFILE(utils/Makefile)
AC_CONFIG_MAKEFILE(projects/Makefile)

dnl Find the install program (needs to be done before canonical stuff)
AC_PROG_INSTALL

dnl Check which host for which we're compiling.  This will tell us which LLVM
dnl compiler will be used for compiling SSA into object code.
AC_CANONICAL_TARGET

dnl Set the "OS" Makefile variable based on the system we are building on.
dnl We will use the build machine information to set some variables.
case $build in
	*-*-linux*)
             AC_SUBST(OS,[Linux])
             platform_type="Linux"
             if test -d /home/vadve/lattner/local/x86/llvm-gcc
	     then
	       AC_SUBST(LLVMGCCDIR,[/home/vadve/lattner/local/x86/llvm-gcc/])
             fi
             ;;
	*-*-solaris*)
             AC_SUBST(OS,[SunOS])
             platform_type="SunOS"
             if test -d /home/vadve/lattner/local/sparc/llvm-gcc
             then
               AC_SUBST(LLVMGCCDIR,[/home/vadve/lattner/local/sparc/llvm-gcc/])
             fi
             ;;
	*-*-cygwin*)
             AC_SUBST(OS,[Cygwin])
             platform_type="Cygwin"
             ;;
	*-*-darwin*)
             AC_SUBST(OS,[Darwin])
             platform_type="Darwin"
             ;;
	*-*-aix*)
             AC_SUBST(OS,[AIX])
             platform_type="AIX"
             ;;
        *-*-interix*)
             AC_SUBST(OS,[SunOS])
             platform_type="SunOS"
             ;;
        *-*-win32*)
             AC_SUBST(OS,[Win32])
             platform_type="Win32"
	     ;;
	*)   
             AC_SUBST(OS,[Unknown])
             platform_type="Unknown"
	     ;;
esac

dnl Make sure we aren't attempting to configure for an unknown system
if test $platform_type -eq "Unknown" ; then
  AC_MSG_ERROR([Platform is unknown, configure can't continue])
fi

dnl Make a link from lib/System/platform to lib/System/$platform_type
dnl This helps the #inclusion of the system specific include files
dnl for the operating system abstraction library
AC_CONFIG_LINKS(lib/System/platform:lib/System/$platform_type)

dnl If we are targetting a Sparc machine running Solaris, pretend that it is
dnl V9, since that is all that we support at the moment, and autoconf will only
dnl tell us we're a sparc.
case $target in
	sparc*-*-solaris*)  AC_SUBST(target,[[sparcv9-sun-solaris2.8]])
	                    ;;
esac

dnl Determine what our target architecture is and configure accordingly.
dnl This will allow Makefiles to make a distinction between the hardware and
dnl the OS.
case $target in
	i*86-*)           AC_SUBST(ARCH,[x86])
	                  ;;
	sparc*-*)         AC_SUBST(ARCH,[Sparc])
	                  ;;
	powerpc*-*)       AC_SUBST(ARCH,[PowerPC])
	                  ;;
	*)                AC_SUBST(ARCH,[Unknown])
	                  ;;
esac

dnl Check for compilation tools
AC_PROG_CXX
AC_PROG_CC(gcc)
AC_PROG_CPP

dnl Ensure that compilation tools are GCC; we use GCC specific extensions
if test "$GCC" != "yes"
then
	AC_MSG_ERROR([gcc required but not found])
fi
if test "$GXX" != "yes"
then
	AC_MSG_ERROR([g++ required but not found])
fi

dnl Verify that GCC is version 3.0 or higher
gccmajor=`$CC --version | head -n 1 | awk '{print $NF;}' | cut -d. -f1`
if test "$gccmajor" -lt "3"
then
	AC_MSG_ERROR([gcc 3.x required, but you have a lower version])
fi

dnl Check for GNU Make.  We use its extensions too, so don't build without it
CHECK_GNU_MAKE
if test -z "$_cv_gnu_make_command"
then
	AC_MSG_ERROR([GNU Make required but not found])
fi

dnl Checks for other tools
AC_PROG_FLEX
AC_PROG_BISON
AC_PROG_LIBTOOL

dnl Checks for tools we can get away with not having:
AC_PATH_PROG(DOT,[dot],[true dot])
AC_PATH_PROG(ETAGS,[etags],[true etags])
dnl Check if we know how to tell etags we are using C++:
etags_version=`$ETAGS --version 2>&1`
case "$etags_version" in
	*[Ee]xuberant*) ETAGSFLAGS="--language-force=c++" ;;
	*GNU\ Emacs*) ETAGSFLAGS="-l c++" ;;
	*) ETAGSFLAGS="" ;;
esac
AC_SUBST(ETAGSFLAGS,$ETAGSFLAGS)
AC_PATH_PROG(PYTHON,[python],[true python])
if test "$PYTHON" = "false"
then
	AC_MSG_WARN([Python is required for the test suite, but it was not found])
fi
AC_PATH_PROG(QMTEST,[qmtest],[true qmtest])
if test "$QMTEST" = "false"
then
	AC_MSG_WARN([QMTest is required for the test suite, but it was not found])
fi

dnl Verify that the version of python available is high enough for qmtest
pyversion=`$PYTHON -V 2>&1 | cut -d\  -f2`
pymajor=`echo $pyversion | cut -d. -f1`
pyminor=`echo $pyversion | cut -d. -f2`

if test "$pymajor" -ge "2"
then
	if test "$pymajor" -eq "2"
	then
		if test "$pyminor" -lt "2"
		then
			AC_MSG_WARN([QMTest requires Python 2.2 or later])
		fi
	fi
else
	AC_MSG_WARN([QMTest requires Python 2.2 or later])
fi

dnl Verify that the source directory is valid
AC_CONFIG_SRCDIR(["Makefile.config.in"])

dnl Checks for libraries:
dnl libelf is for sparc only; we can ignore it if we don't have it
AC_CHECK_LIB(elf, elf_begin)

dnl dlopen() is required for plugin support.
AC_SEARCH_LIBS(dlopen,dl,AC_DEFINE([HAVE_DLOPEN],[1],[Define if dlopen() is available on this platform.]),AC_MSG_WARN([dlopen() not found - disabling plugin support]))

dnl mallinfo is optional; the code can compile (minus features) without it
AC_SEARCH_LIBS(mallinfo,malloc,AC_DEFINE([HAVE_MALLINFO],[1],[Define if mallinfo() is available on this platform.]))

dnl pthread locking functions are optional - but llvm will not be thread-safe
dnl without locks.
AC_SEARCH_LIBS(pthread_mutex_lock,pthread,HAVE_PTHREAD_MUTEX_LOCK=1,HAVE_PTHREAD_MUTEX_LOCK=0)
AC_SUBST(HAVE_PTHREAD_MUTEX_LOCK)

dnl Checks for header files.
dnl We don't check for ancient stuff or things that are guaranteed to be there
dnl by the C++ standard. We always use the <cfoo> versions of <foo.h> C headers.
AC_HEADER_STDC
AC_HEADER_SYS_WAIT

dnl Checks for POSIX and other various system-specific header files
AC_CHECK_HEADERS(fcntl.h limits.h sys/time.h unistd.h malloc.h sys/mman.h sys/resource.h dlfcn.h link.h execinfo.h windows.h)

dnl Check for things that need to be included in public headers, and so
dnl for which we may not have access to a HAVE_* preprocessor #define.
dnl (primarily used in DataTypes.h)
AC_CHECK_HEADER([sys/types.h],
                [INCLUDE_SYS_TYPES_H='#include <sys/types.h>'],
                [INCLUDE_SYS_TYPES_H=''])
AC_SUBST(INCLUDE_SYS_TYPES_H)
AC_CHECK_HEADER([inttypes.h],
                [INCLUDE_INTTYPES_H='#include <inttypes.h>'],
                [INCLUDE_INTTYPES_H=''])
AC_SUBST(INCLUDE_INTTYPES_H)
AC_CHECK_HEADER([stdint.h],
                [INCLUDE_STDINT_H='#include <stdint.h>'],
                [INCLUDE_STDINT_H=''])
AC_SUBST(INCLUDE_STDINT_H)


dnl Check for types
AC_TYPE_PID_T
AC_TYPE_SIZE_T
AC_CHECK_TYPES([int64_t],,AC_MSG_ERROR([Type int64_t required but not found]))
AC_CHECK_TYPES([uint64_t],,AC_MSG_ERROR([Type uint64_t required but not found]))
AC_HEADER_TIME
AC_STRUCT_TM

dnl Check for various C features
AC_C_PRINTF_A

dnl Check for the endianness of the target
AC_C_BIGENDIAN(AC_SUBST([ENDIAN],[big]),AC_SUBST([ENDIAN],[little]))

dnl Check for C++ extensions
AC_CXX_HAVE_HASH_MAP
AC_CXX_HAVE_HASH_SET
AC_CXX_HAVE_STD_ITERATOR
AC_CXX_HAVE_BI_ITERATOR
AC_CXX_HAVE_FWD_ITERATOR

AC_FUNC_ISNAN
AC_FUNC_ISINF

dnl Checks for library functions.
AC_FUNC_ALLOCA
AC_FUNC_MMAP
if test "$ac_cv_func_mmap_fixed_mapped" = "no"
then
	AC_MSG_WARN([mmap() required but not found])
fi
AC_FUNC_MMAP_FILE
if test "$ac_cv_func_mmap_file" = "no"
then
	AC_MSG_WARN([mmap() of files required but not found])
fi
AC_HEADER_MMAP_ANONYMOUS
AC_TYPE_SIGNAL
AC_CHECK_FUNCS(getcwd gettimeofday strdup strtoq strtoll backtrace isatty mkstemp getrusage)
AC_CHECK_FUNC(mprotect,,AC_MSG_ERROR([Function mprotect() required but not found]))

dnl Determine if the linker supports the -R option.
AC_LINK_USE_R

dnl --enable/--with command-line options:
dnl Check whether they want to do an optimized build:
AC_ARG_ENABLE(optimized,AC_HELP_STRING([--enable-optimized],[Compile with optimizations enabled (default is NO)]),,enableval=no)
if test ${enableval} = "no"
then
	AC_SUBST(ENABLE_OPTIMIZED,[[]])
else
	AC_SUBST(ENABLE_OPTIMIZED,[[ENABLE_OPTIMIZED=1]])
fi

AC_DEFUN(EXTERNAL_BENCHMARK,
[m4_define([allcapsname],translit($1,a-z,A-Z))
 AC_ARG_ENABLE($1,
 AC_HELP_STRING([--enable-$1=ARG], 
                [Use $1 as a benchmark (srcs in DIR)]),
 checkresult=$enableval,
 checkresult=auto)
AC_MSG_CHECKING([for $1 benchmark sources])
case "$checkresult" in
auto|yes)
    defaultdir=$2
	if test -d "$defaultdir"
	then
		AC_SUBST(allcapsname()[_ROOT],[$defaultdir])
		AC_SUBST([USE_]allcapsname(),[USE_]allcapsname()=1)
        checkresult="yes, found in $defaultdir"
    else
        checkresult=no
    fi
    ;;
no)
    AC_SUBST(allcapsname()[_ROOT],[])
    AC_SUBST([USE_]allcapsname(),[])
    checkresult=no
    ;;
*)  if test -d "$checkresult"
    then
        AC_SUBST(allcapsname()[_ROOT],"$checkresult")
        AC_SUBST([USE_]allcapsname(),[USE_]allcapsname()=1)
        checkresult="yes, in $checkresult"
    else
        AC_SUBST(allcapsname()[_ROOT],[])
        AC_SUBST([USE_]allcapsname(),[])
        checkresult="no, not found in $checkresult"
    fi
    ;;
esac
AC_MSG_RESULT($checkresult)
m4_undefine([allcapsname])
])

EXTERNAL_BENCHMARK(spec95,/home/vadve/shared/benchmarks/spec95/benchspec)
EXTERNAL_BENCHMARK(spec2000,/home/vadve/shared/benchmarks/speccpu2000/benchspec)
EXTERNAL_BENCHMARK(povray,/home/vadve/shared/benchmarks/povray31)

dnl Precompiled Bytecode Option
AC_ARG_ENABLE(precompiled_bytecode,AC_HELP_STRING([--enable-precompiled_bytecode],[Use pre-compiled bytecode (default is NO)]),,enableval=no)
if test ${enableval} = "no"
then
	AC_SUBST(UPB,[[]])
else
	AC_SUBST(UPB,[[USE_PRECOMPILED_BYTECODE=1]])
fi

dnl LLC Diff Option
AC_ARG_ENABLE(llc_diffs,AC_HELP_STRING([--enable-llc_diffs],[Enable LLC Diffs when testing (default is YES)]),,enableval=yes)
if test ${enableval} = "no"
then
	AC_SUBST(DISABLE_LLC_DIFFS,[DISABLE_LLC_DIFFS:=1])
else
	AC_SUBST(DISABLE_LLC_DIFFS,[[]])
fi

dnl JIT Option
AC_ARG_ENABLE(jit,AC_HELP_STRING([--enable-jit],[Enable Just In Time Compiling (default is YES)]),,enableval=default)
if test ${enableval} = "no"
then
	AC_SUBST(JIT,[[]])
else
	case $target in
		*i*86*)
			AC_SUBST(JIT,[[TARGET_HAS_JIT=1]])
			;;
		*sparc*)
			AC_SUBST(JIT,[[TARGET_HAS_JIT=1]])
			;;
		*)
			AC_SUBST(JIT,[[]])
			;;
	esac
fi

dnl Find the LLVM GCC-based C/C++ front end
AC_ARG_WITH(llvmgccdir,AC_HELP_STRING([--with-llvmgccdir],[Location of LLVM GCC front-end]),AC_SUBST(LLVMGCCDIR,[$withval]))
AC_MSG_CHECKING([for llvm-gcc])
LLVM_GCC_CHECK=no
if test -d "$LLVMGCCDIR"
then
	if test -x "$LLVMGCCDIR/bin/gcc"
	then
		LLVM_GCC_CHECK="$LLVMGCCDIR/bin/gcc"
	fi
fi
llvmgccwarn=no
AC_MSG_RESULT($LLVM_GCC_CHECK)
if test "$LLVM_GCC_CHECK" = "no"
then
    llvmgccwarn=yes
fi
AC_MSG_CHECKING([whether llvm-gcc is sane])
LLVM_GCC_SANE=no
if test -x "$LLVM_GCC_CHECK"
then
	cp /dev/null conftest.c
    "$LLVM_GCC_CHECK" -S -o - conftest.c | grep implementation > /dev/null 2>&1
	if test $? -eq 0
	then
		LLVM_GCC_SANE=yes
	fi
	rm conftest.c
	llvmcc1path=`"$LLVM_GCC_CHECK" --print-prog-name=cc1`
	AC_SUBST(LLVMCC1,$llvmcc1path)
	llvmcc1pluspath=`"$LLVM_GCC_CHECK" --print-prog-name=cc1plus`
	AC_SUBST(LLVMCC1PLUS,$llvmcc1pluspath)
fi
AC_MSG_RESULT($LLVM_GCC_SANE)
if test "$LLVM_GCC_SANE" = "no"
then
	llvmgccwarn=yes
fi

dnl Location of the bytecode repository
AC_ARG_WITH(bcrepos,AC_HELP_STRING([--with-bcrepos],[Location of Bytecode Repository]),AC_SUBST(BCR,[$withval]),AC_SUBST(BCR,[/home/vadve/lattner/LLVMPrograms]))

dnl Location of PAPI
AC_ARG_WITH(papi,AC_HELP_STRING([--with-papi],[Location of PAPI]),AC_SUBST(PAPIDIR,[$withval]),AC_SUBST(PAPIDIR,[/home/vadve/shared/Sparc/papi-2.3.4.1]))

dnl Get libtool's idea of what the shared library suffix is.
dnl (This is a hack; it relies on undocumented behavior.)
AC_MSG_CHECKING([for shared library suffix])
eval "SHLIBEXT=$shrext"
AC_MSG_RESULT($SHLIBEXT)
dnl Propagate it to the Makefiles and config.h (for gccld & bugpoint).
AC_SUBST(SHLIBEXT,$SHLIBEXT)
AC_DEFINE_UNQUOTED(SHLIBEXT,"$SHLIBEXT",
                   [Extension that shared libraries have, e.g., ".so".])

# Translate the various configuration directories and other basic
# information into substitutions that will end up in config.h.in so
# that these configured values can be hard-wired into a program.
eval LLVM_PREFIX="${prefix}";
eval LLVM_BINDIR="${prefix}/bin";
eval LLVM_LIBDIR="${prefix}/lib";
eval LLVM_DATADIR="${prefix}/data";
eval LLVM_DOCSDIR="${prefix}/docs";
eval LLVM_ETCDIR="${prefix}/etc";
eval LLVM_INCLUDEDIR="${prefix}/include";
eval LLVM_INFODIR="${prefix}/info";
eval LLVM_MANDIR="${prefix}/man";
LLVM_CONFIGTIME=`date`
AC_SUBST(LLVM_PREFIX)
AC_SUBST(LLVM_BINDIR)
AC_SUBST(LLVM_LIBDIR)
AC_SUBST(LLVM_DATADIR)
AC_SUBST(LLVM_DOCSDIR)
AC_SUBST(LLVM_ETCDIR)
AC_SUBST(LLVM_INCLUDEDIR)
AC_SUBST(LLVM_INFODIR)
AC_SUBST(LLVM_MANDIR)
AC_SUBST(LLVM_CONFIGTIME)
AC_DEFINE_UNQUOTED(LLVM_PREFIX,"$LLVM_PREFIX", [Installation prefix directory])
AC_DEFINE_UNQUOTED(LLVM_BINDIR, "$LLVM_BINDIR", [Installation directory for binary executables])
AC_DEFINE_UNQUOTED(LLVM_LIBDIR, "$LLVM_LIBDIR", [Installation directory for libraries])
AC_DEFINE_UNQUOTED(LLVM_DATADIR, "$LLVM_DATADIR", [Installation directory for data files])
AC_DEFINE_UNQUOTED(LLVM_DATADIR, "$LLVM_DOCSDIR", [Installation directory for documentation])
AC_DEFINE_UNQUOTED(LLVM_ETCDIR, "$LLVM_ETCDIR", [Installation directory for config files])
AC_DEFINE_UNQUOTED(LLVM_INCLUDEDIR, "$LLVM_INCLUDEDIR", [Installation directory for include files])
AC_DEFINE_UNQUOTED(LLVM_INFODIR, "$LLVM_INFODIR", [Installation directory for .info files])
AC_DEFINE_UNQUOTED(LLVM_MANDIR, "$LLVM_MANDIR", [Installation directory for man pages])
AC_DEFINE_UNQUOTED(LLVM_CONFIGTIME, "$LLVM_CONFIGTIME", [Time at which LLVM was configured])

dnl Create the output files
AC_OUTPUT()

dnl Warn loudly if llvm-gcc was not obviously working
if test $llvmgccwarn = yes
then
	AC_MSG_WARN([***** llvm C/C++ front end was not found, or does not])
	AC_MSG_WARN([***** appear to be working.])
	AC_MSG_WARN([***** ])
	AC_MSG_WARN([***** Please check configure's --with-llvmgccdir option.])
	AC_MSG_WARN([***** Runtime libraries (in llvm/runtime) will not be built,])
	AC_MSG_WARN([***** but you should be able to build the llvm tools.])
fi