input: calloc minimization for xi2mask_new
There's no reason to do this as (nmasks + 2) callocs, and it's a
surprisingly hot path. Turns out you hit this ~once per passive grab,
and you do a few bajillion passive grab changes every time you enter or
leave the overview in gnome-shell. According to a callgrind of Xorg
with gnome-shell-perf-tool run against it:
Ir before:
721437275
Ir after:
454227086
Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jasper St. Pierre <jstpierre@mecheye.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>