not reviewing everything, but

 - libffi_ios* will be bitrot.  I understand that you'll
   need an unreleased version, however I would much
   prefer that any additional patches are added in the
   repo, and maybe then patching libffi from the iOS build
   system. This way the code will see updates when libffi
   is updated.

 - I don't like the copies of Setup.*. Again this will
   bitrot. Please see
   http://bazaar.launchpad.net/~doko/python/pkg3.4-debian/view/head:/rules
   search for "define __post_configure"
   Basically this patches Setup.dist to build a bunch
   of extensions statically.  Can you use something
   similar, or improve that?

 - the change to setup.py might deserve a comment.

 - are constants in plat-ios really the same for every
   architecture?

 - how is the gnu triplet / quadruplet called for iOS?