github pull requests for libffi

[Anthony Green <green at moxielogic dot com>]

Happy New Year, everybody!

I've recently switched how I'm maintaining libffi source in github.
Rather than use quilt to maintain a series of patches on top of the
GCC libffi sources, I've placed the GCC sources on a GCC branch of
libffi and plan to cherry-pick patches from there into the trunk.  All
of the quilt bits are gone from the repo.

This means I can now easily accept github pull requests for changes.
Please try to remember to include ChangeLog entries with your patches.

Thanks!

Anthony Green