Fix FreeBSD

ci/Vagrantfile

ci/run-travis.sh

libc-test/build.rs

src/unix/bsd/apple/mod.rs

src/unix/bsd/freebsdlike/freebsd.rs

src/unix/bsd/freebsdlike/mod.rs

src/unix/bsd/mod.rs

src/unix/bsd/openbsdlike/mod.rs

src/unix/mod.rs

src/unix/notbsd/mod.rs