Initial support for being able to specify the llvm-gcc to use like this:
  --with-llvmgcc="gcc-4.5 -fplugin=dragonegg.so"


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120149 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 74cb0aa..38d2f08 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -1425,10 +1425,9 @@
 dnl Check wether llvm-gcc is based on dragonegg
 AC_CACHE_CHECK([whether llvm-gcc is dragonegg],[llvm_cv_llvmgcc_dragonegg],
 [llvm_cv_llvmgcc_dragonegg="no"
-if test -x "$LLVMGCC" ; then
+if test -n "$LLVMGCC" ; then
   cp /dev/null conftest.c
-  "$LLVMGCC" -fplugin-arg-dragonegg-emit-ir -S -o - conftest.c | \
-  grep 'target datalayout =' > /dev/null 2>&1
+  $LLVMGCC -fplugin-arg-dragonegg-emit-ir -S -o - conftest.c > /dev/null 2>&1
   if test $? -eq 0 ; then
     llvm_cv_llvmgcc_dragonegg="yes"
   fi
@@ -1450,9 +1449,9 @@
 dnl See if the llvm-gcc executable can compile to LLVM assembly
 AC_CACHE_CHECK([whether llvm-gcc is sane],[llvm_cv_llvmgcc_sanity],
 [llvm_cv_llvmgcc_sanity="no"
-if test -x "$LLVMGCC" ; then
+if test -n "$LLVMGCC" ; then
   cp /dev/null conftest.c
-  "$LLVMGCC" "$LLVMCC_EMITIR_FLAG" -S -o - conftest.c | \
+  $LLVMGCC "$LLVMCC_EMITIR_FLAG" -S -o - conftest.c | \
       grep 'target datalayout =' > /dev/null 2>&1
   if test $? -eq 0 ; then
     llvm_cv_llvmgcc_sanity="yes"
@@ -1464,13 +1463,13 @@
 dnl Furthermore, add some information about the tools
 if test "$llvm_cv_llvmgcc_sanity" = "yes" ; then
   AC_MSG_CHECKING([llvm-gcc component support])
-  llvmcc1path=`"$LLVMGCC" --print-prog-name=cc1`
+  llvmcc1path=`$LLVMGCC --print-prog-name=cc1`
   AC_SUBST(LLVMCC1,$llvmcc1path)
-  llvmcc1pluspath=`"$LLVMGCC" --print-prog-name=cc1plus`
+  llvmcc1pluspath=`$LLVMGCC --print-prog-name=cc1plus`
   AC_SUBST(LLVMCC1PLUS,$llvmcc1pluspath)
   llvmgccdir=`echo "$llvmcc1path" | sed 's,/libexec/.*,,'`
   AC_SUBST(LLVMGCCDIR,$llvmgccdir)
-  llvmgcclangs=[`"$LLVMGCC" -v --help 2>&1 | grep '^Configured with:' | sed 's/^.*--enable-languages=\([^ ]*\).*/\1/'`]
+  llvmgcclangs=[`$LLVMGCC -v --help 2>&1 | grep '^Configured with:' | sed 's/^.*--enable-languages=\([^ ]*\).*/\1/'`]
   AC_SUBST(LLVMGCC_LANGS,$llvmgcclangs)
   AC_SUBST(LLVMGCC_DRAGONEGG,$llvm_cv_llvmgcc_dragonegg)
   AC_SUBST(LLVMGCC_DISABLEOPT_FLAGS)