Defines starting with `n' in src

• NF_SUBSECTOR src/doomdata.h:92
• NOSELENGTH src/am_main.c:22
• NULL src/doomdef.h:58
• NUMENDOBJ src/f_main.c:141
• NUMFACES src/st_main.h:48
• NUMLCHARS src/m_main.c:9
• NUMMICROS src/st_main.h:65
• NUM_OLD_CHANNELS src/sound.h:8
• NUM_OUTPUT_CHANNELS src/sound.h:2
• NUMSPLATS src/st_main.h:64