Add _exit.
Add _exit.

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