Downgrade the invalid offsetof error to a warning.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70634 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 33d308e..dc058b2 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4777,9 +4777,9 @@
       RecordDecl *RD = RC->getDecl();
       if (CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
         if (!CRD->isPOD())
-          return ExprError(Diag(BuiltinLoc, diag::err_offsetof_non_pod_type)
-                   << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
-                   << Res->getType());
+          ExprError(Diag(BuiltinLoc, diag::warn_offsetof_non_pod_type)
+            << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
+            << Res->getType());
       }
       
       FieldDecl *MemberDecl