Implement: <rdar://problem/6351970> rule request: warn if @synchronized mutex can be nil

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113573 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/GRExprEngineInternalChecks.h b/lib/Checker/GRExprEngineInternalChecks.h
index f91a759..740a914 100644
--- a/lib/Checker/GRExprEngineInternalChecks.h
+++ b/lib/Checker/GRExprEngineInternalChecks.h
@@ -31,6 +31,7 @@
 void RegisterDivZeroChecker(GRExprEngine &Eng);
 void RegisterFixedAddressChecker(GRExprEngine &Eng);
 void RegisterNoReturnFunctionChecker(GRExprEngine &Eng);
+void RegisterObjCAtSyncChecker(GRExprEngine &Eng);
 void RegisterPointerArithChecker(GRExprEngine &Eng);
 void RegisterPointerSubChecker(GRExprEngine &Eng);
 void RegisterReturnPointerRangeChecker(GRExprEngine &Eng);