Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1545,7 +1545,7 @@
     frontend::IncludeDirGroup Group = frontend::System;
     if (A->getOption().matches(OPT_internal_externc_isystem))
       Group = frontend::ExternCSystem;
-    Opts.AddPath(A->getValue(), Group, false, true);
+    Opts.AddPath(A->getValue(), Group, false, false);
   }
 
   // Add the path prefixes which are implicitly treated as being system headers.