Here's an update to libgit2 1.0.0. lang/rust-nightly looks for it
now and is currently patched to look for 0.99.0 (not good).
I have no idea if the rubygem stuff is correct or even if the runtime
works. Maybe rubygem-rugged should not be updated yet.
devel/gitaly failed to build for me but that is presumably fixed.
I'll retest and patch it later I guess.