Hmm. I introduced this because the Apple gcc/clang on my box (also 10.9.2) was spewing warnings without it and now compiles warning free.

If I type `gcc --version` on my box, I see:

```sh
$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.1.0
Thread model: posix
```

What do you get?