autoconf: Introduce --with-clang-srcdir, to build out-of-tree clang as tools/clang on tools/Makefile.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142102 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 128dd7f..b8b61bc 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -795,6 +795,17 @@
*) AC_MSG_ERROR([Invalid path for --with-ocaml-libdir. Provide full path]) ;;
esac
+AC_ARG_WITH(clang-srcdir,
+ AS_HELP_STRING([--with-clang-srcdir],
+ [Directory to the out-of-tree Clang source]),,
+ withval="-")
+case "$withval" in
+ -) clang_src_root="" ;;
+ /* | [[A-Za-z]]:[[\\/]]*) clang_src_root="$withval" ;;
+ *) clang_src_root="$ac_pwd/$withval" ;;
+esac
+AC_SUBST(CLANG_SRC_ROOT,[$clang_src_root])
+
AC_ARG_WITH(clang-resource-dir,
AS_HELP_STRING([--with-clang-resource-dir],
[Relative directory from the Clang binary for resource files]),,