This is also an issue for clang builds of Python on FreeBSD and results in the _ctypes extension failing to compile (See: koobs-freebsd-clang buildbot)

The original mozilla patch (see References below) did not make it into the libffi 3.0.11 release, which has already been committed to the Cpython tree (see #15194)

Attached here is the original Mozilla patch to configure & configure.ac which I have included in a PR submitted to the FreeBSD ports tree for python27

The PR includes test builds with gcc and clang on multiple FreeBSD versions and architectures, along with a libffi unit test run with clang (http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/171768)

I propose this patch be committed to all branches to re-enable _ctypes extension builds with clang.

References:

- http://www.cygwin.com/ml/libffi-discuss/2011/msg00024.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=631928
- https://github.com/atgreen/libffi/issues/21
- https://bugs.gentoo.org/show_bug.cgi?id=417179
- http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/171768