build libffi under MSWin32 with MSYS
build dll under windows
croak on error
use o2dll to build a dll
using CBuilder results in a dll that doesn't export anything
but the XS boot code
travis: use dzil authordeps instead of hardcoding modules
MANIFEST: skip *.info too
Changes: update
Revert "travis: use dzil authordeps instead of hardcoding modules"

This reverts commit abbd8907c27a4c35b14484cc6eee727b5ceafe53.
travis: add Dist::Zilla::Plugin::OSPrereqs to depends
dist.ini: exclude Alien::o2dll from AutoPrereqs