Don't complain about -fobjc-link-runtime being unused with -fobjc-arc.

If you build with -fobjc-arc, then -fobjc-link-runtime is implied but we
don't need to warn about it being unused in that case.  rdar://12039965

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161444 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/arclite-link.c b/test/Driver/arclite-link.c
index 735555f..3471bf6 100644
--- a/test/Driver/arclite-link.c
+++ b/test/Driver/arclite-link.c
@@ -11,3 +11,7 @@
 // CHECK-ARCLITE-OSX: -lobjc
 // CHECK-NOARCLITE-NOT: libarclite
 // CHECK-NOSTDLIB-NOT: -lobjc
+
+// RUN: %clang -### -target x86_64-apple-darwin10 -fobjc-link-runtime -fobjc-arc -mmacosx-version-min=10.7 %s 2>&1 | FileCheck -check-prefix=CHECK-UNUSED %s
+
+// CHECK-UNUSED-NOT: warning: argument unused during compilation: '-fobjc-link-runtime'