autoconf: restore old clang-srcdir behavior

Keep the string empty when unspecified. Undoes
part of r149563.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149568 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index ad44a630ac018d5401474fdc5780e9e409800fe6..c9757d9ff7b7f6cbcd89f66e0874375a7ccdd528 100644 (file)
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -813,7 +813,7 @@ AC_ARG_WITH(clang-srcdir,
     [Directory to the out-of-tree Clang source]),,
     withval="-")
 case "$withval" in
-  -) clang_src_root="$ac_pwd/tools/clang" ;;
+  -) clang_src_root="" ;;
   /* | [[A-Za-z]]:[[\\/]]*) clang_src_root="$withval" ;;
   *) clang_src_root="$ac_pwd/$withval" ;;
 esac
@@ -1588,6 +1588,9 @@ dnl Configure doxygen's configuration file
 AC_CONFIG_FILES([docs/doxygen.cfg])
 
 dnl Configure clang, if present
+if test ${clang_src_root} = ""; then
+  clang_src_root="$ac_pwd/tools/clang"
+fi
 if test -f ${clang_src_root}/README.txt; then
   AC_CONFIG_HEADERS([${clang_src_root}/include/clang/Config/config.h])
   AC_CONFIG_FILES([${clang_src_root}/docs/doxygen.cfg])