Handle weakref in cases where target is not an IDENTIFIER_NODE.

These two test cases now also match the output produced by clang. Fixes
building llvm with gcc 4.6 + dragonegg.

git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@194730 91177308-0d34-0410-b5e6-96231b3b80d8