specs: convert socket tests from issue #92 to specl.
specs: convert socket tests from issue #92 to specl.

* specs/posix_spec.yaml (socket handling): New spec, not working
on Mountain Lion, at least :(
Awaiting feedback, see issue #92.
Reported by zevv@github, from a patch by Ico Doornekamp.

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@gnu.org>

ardje/luaposix,luaposix/luaposix,snegovick/luaposix,jimmyharris/luaposix,rrthomas/luaposix,ardje/luaposix,snegovick/luaposix,zevv/luaposix,rrthomas/luaposix,zevv/luaposix,jimmyharris/luaposix