[C2hs] Patch to work with ghc 6.12.

Hi. I've ported the patch of Duncan Coutts to the internal c2hs of gtk2hs to make it build with ghc 6.12, and applied it to version 0.16.0 of c2hs. The patch is attached, and I'm using it in Debian, since the current version of ghc6 in sid is 6.12.1. Greetings. -- marcot http://marcot.iaaeee.org/