Poll with zero timeout

Poll with zero timeout

Jean-Christian de Rivaz writes:
The attached patch solve an issue I faced while using the libdbus-glib
waiting for a D-Bus message or the end of a glib timer at the same time.
This specific case of use generate a poll call with a zero timeout. On
platformes with the glibc a zero timeout poll return immetiately even if
there is no file descriptor event. But on platformes with uClibc a zero
timeout poll block until a file descriptor event occurs.