remove deps from ship target

i think the gemspec needs to somehow be re-evaluated after doing
the clean and prep stages, but that needs to be parsed early to
setup the rake extensiontask stuff, so really the files in the
gemspec need to not be mutated by clean+prep tasks (but the git
trick everyone uses doesn't work here because not all our files
we ship are checked into git..).
fix __GCC__ to __GNUC__