Only enable the ObjCAtSyncChecker when the translation unit uses Objective-C.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118414 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Checker/ObjCAtSyncChecker.cpp

@@ -33,7 +33,9 @@ public:
 } // end anonymous namespace
 
 void clang::RegisterObjCAtSyncChecker(GRExprEngine &Eng) {
-  Eng.registerCheck(new ObjCAtSyncChecker());
+  // @synchronized is an Objective-C 2 feature.
+  if (Eng.getContext().getLangOptions().ObjC2)
+    Eng.registerCheck(new ObjCAtSyncChecker());
 }
 
 void ObjCAtSyncChecker::PreVisitObjCAtSynchronizedStmt(CheckerContext &C,