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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66335 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 92bc0bc..28cb9bf 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -52,7 +52,7 @@
   class TypedefDecl;
   class FunctionDecl;
   class QualType;
-  struct LangOptions;
+  class LangOptions;
   class Token;
   class IntegerLiteral;
   class StringLiteral;
@@ -79,7 +79,7 @@
   class ObjCContainerDecl;
   struct BlockSemaInfo;
   class BasePaths;
-  class MemberLookupCriteria;
+  struct MemberLookupCriteria;
 
 /// Sema - This implements semantic analysis and AST building for C.
 class Sema : public Action {