more elegant posix spawn; squashed debug print
more elegant posix spawn; squashed debug print

stevedonovan/luabuild,andrew-d/luabuild,yuhangwang/luabuild,yuhangwang/luabuild,yuhangwang/luabuild,stevedonovan/luabuild,stevedonovan/luabuild,stevedonovan/luabuild,yuhangwang/luabuild,andrew-d/luabuild,andrew-d/luabuild,stevedonovan/luabuild,yuhangwang/luabuild,andrew-d/luabuild,andrew-d/luabuild