Some struct/class mismatch fixes, to silence MSVC warnings.

llvm-svn: 66335
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 76ab0f8..c3a84af 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -51,7 +51,7 @@
   class NamedDecl;
   class ValueDecl;
   class VarDecl;
-  struct LangOptions;
+  class LangOptions;
   class Diagnostic;
   class AnnotateAttr;