[modules] When a .pcm file is explicitly built separately from the translation
unit, allow the -O settings of the two compilations to differ.

llvm-svn: 220943
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 1d8c6a1..bd81c0d 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -508,8 +508,8 @@
       : PP(PP), Context(Context), LangOpt(LangOpt), TargetOpts(TargetOpts),
         Target(Target), Counter(Counter), InitializedLanguage(false) {}
 
-  bool ReadLanguageOptions(const LangOptions &LangOpts,
-                           bool Complain) override {
+  bool ReadLanguageOptions(const LangOptions &LangOpts, bool Complain,
+                           bool AllowCompatibleDifferences) override {
     if (InitializedLanguage)
       return false;