back out r149504

Too many weird build failures.

llvm-svn: 149571
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 5248c2e..89e0600 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -36,9 +36,12 @@
 #include "InputInfo.h"
 #include "ToolChains.h"
 
-#include <map>
+#ifdef HAVE_CLANG_CONFIG_H
+# include "clang/Config/config.h"
+#endif
+#include "llvm/Config/config.h"
 
-#include "clang/Config/config.h"
+#include <map>
 
 using namespace clang::driver;
 using namespace clang;