Coreutils/gettext on darwin take 2

See https://github.com/NixOS/nixpkgs/pull/902

After that PR, I've upgraded the OS compiler.

I've now done the following:

- Uninstalled the 4.1 devtools with `sudo /Library/Developer/4.1/uninstall-devtools --mode=all`
- Installed the official Command Line Tools for Xcode for Lion from http://developer.apple.com/downloads

So the OS compiler is now:

```
$ gcc --version
i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)
```