Every screen region consists of a single rectangle, so initializing a
stack-allocated region for each screen on-demand does no heap allocation
and is fast.
This eliminates a MAXSCREENS-sized array.
The REGION_UNINIT calls are no-ops since no boxes are actually allocated
for a single-rectangle region, but it seemed wiser to include them.
Signed-off-by: Jamey Sharp <jamey@minilop.net>
Reviewed-by: Tiago Vignatti <tiago.vignatti@nokia.com>
Tested-by: Tiago Vignatti <tiago.vignatti@nokia.com> (i686 GNU/Linux)