libffi changes for 3.0.11

[Anthony Green]

I just released 3.0.10.  Thanks to everybody who contributed!

My plan is to release 3.0.11 within a couple of weeks.  It will contain 
the soname bump (since I've removed debug symbols, again), and I also 
want to get David Gilbert's variadic function support in there.

I am not able to personally test every platform that libffi purports to 
support, so please test and post your results here:
  http://moxielogic.org/wiki/index.php?title=Libffi_3.0.11

Thanks!

AG