Set maximum width(/height) in one place

Should also fix https://savannah.gnu.org/bugs/?38940

Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>
fix: screen -ls always exits with 1

bug https://savannah.gnu.org/bugs/?43238

Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>