Driver: Fix clang -ccc-no-clang -x c++-header foo.h on Darwin.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95876 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 9e7ec3b..f3b19f5 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1746,7 +1746,8 @@
   else if (Output.getType() == types::TY_AST)
     D.Diag(clang::diag::err_drv_no_ast_support)
       << getToolChain().getTripleString();
-  else if (JA.getType() != types::TY_PP_Asm)
+  else if (JA.getType() != types::TY_PP_Asm &&
+           JA.getType() != types::TY_PCH)
     D.Diag(clang::diag::err_drv_invalid_gcc_output_type)
       << getTypeName(JA.getType());