Modular Codegen: Separate flags for function and debug info support

This allows using and testing these two features separately. (noteably,
debug info is, so far as I know, always a win (basically). But function
modular codegen is currently a loss for highly optimized code - where
most of the linkonce_odr definitions are optimized away, so providing
weak_odr definitions is only overhead)

llvm-svn: 300104
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 8196c8d..812cd9e 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -2228,10 +2228,10 @@
   Writer->ClearSwitchCaseIDs();
 
   assert(FD->doesThisDeclarationHaveABody());
-  bool ModularCodegen = Writer->Context->getLangOpts().ModularCodegen &&
+  bool ModulesCodegen = Writer->Context->getLangOpts().ModulesCodegen &&
                         Writer->WritingModule && !FD->isDependentContext();
-  Record->push_back(ModularCodegen);
-  if (ModularCodegen)
+  Record->push_back(ModulesCodegen);
+  if (ModulesCodegen)
     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
     Record->push_back(CD->getNumCtorInitializers());