ports/152480: [Patch] fix build of devel/libffi with clang on amd64

[Koop Mast]

Maintainer of devel/libffi,

Please note that PR ports/152480 has just been submitted.

If it contains a patch for an upgrade, an enhancement or a bug fix
you agree on, reply to this email stating that you approve the patch
and a committer will take care of it.

The full text of the PR can be found at:
http://www.freebsd.org/cgi/query-pr.cgi?pr=152480