Variables starting with `n' in src/od-win32

• ncols256 src/od-win32/win32gfx.c:739
• needs_direct src/od-win32/win32gfx.c:44
• nr_joysticks src/od-win32/win32gfx.c:90
• NULL src/od-win32/parser.c:147
• numkeysdown src/od-win32/win32.c:90