Merge pull request #9509 from akyrtzi/persistent-pch-for-build

[Driver/ClangImporter] Changes for the driver to recognize -pch-output-dir and propagate to the frontend invocations

lib/Frontend/CompilerInvocation.cpp

@@ -1132,6 +1132,7 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts,
 
   if (const Arg *A = Args.getLastArg(OPT_pch_output_dir)) {
     Opts.PrecompiledHeaderOutputDir = A->getValue();
+    Opts.PCHDisableValidation |= Args.hasArg(OPT_pch_disable_validation);
   }
 
   return false;