Inspired by Jon Turney's "Xwin: Simplify screen option processing" patch, which does something similar for the Xwin server. Besides making the code more readable, this eliminates most of Xvfb's references to MAXSCREENS. Signed-off-by: Jamey Sharp <jamey@minilop.net> Reviewed-by: Tiago Vignatti <tiago.vignatti@nokia.com>