kgardas authored Nov 01, 2015 and Ben Gamari committed Nov 01, 2015

This patch enforces linkage with pthread library on OpenBSD. This is
done in order to avoid linker errors when linking with libffi which
requires POSIX threading but itself is not linked with libpthread
directly. So client binaries (of libffi) needs to link against
libpthread explicitly

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie, erikd

Differential Revision: https://phabricator.haskell.org/D1410