games/edge: unbreak with clang 4.0
src/p_enemy.cc:531:26: error: ordered comparison between pointer and zero
('struct mobj_s **' and 'int')
if (brain_spots.targets > 0)
~~~~~~~~~~~~~~~~~~~ ^ ~src/w_sprite.cc:578:42: error: ordered comparison between pointer and zero
('spriteframe_c *' and 'int')
if (sprites[states[i].sprite]->frames > 0)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~Reported by: antoine (via exp-run)