Weston should not exit if stdin is a closed stream. This allows
to launch with a closed stdin:
# weston <&-
This fixes screen sharing using weston: Weston closes the stdin
before forking itself to execute the screen sharing instance of
weston. Before this patch screen sharing failed with:
Screen share failed: No wl_shm found
unknown child process exited
Fixes: f0d39b2243e5 ("weston: Set CLOEXEC on stdin")
Signed-off-by: Stefan Agner <stefan@agner.ch>
3b1c1efe34