[HOpenGL] Compiling HOpenGL under recent versions of GHC

Hi there, I just recently installed Gentoo Linux with the intention of using HOpenGL. Unfortunately I'm having problems compiling - something seems to use a "_casm_" directive (I think) and GHC complains that this isn't valid. So far as I can tell it was removed from the language a while ago. Anyway, is this an expected problem or have I misconfigured something? If this isn't a known problem I'll try again and carefully document what I do. Thanks. Regards, Weeble.