All symbols starting with `u' in src

• undefined src/doomdef.h:74
• UNIX src/readme.sound:22
• up src/p_pspr.c:279
• updates src/doomdef.h:122
• UploadNewPalette src/i_viorig:539
• use src/doomdef.h:63
• usecs src/changelog:92
• used src/s_sound.c:111
• usegamma src/v_video.c:137
• usejoystick src/m_misc.c:171
• usemouse src/m_misc.c:170
• using src/p_spec.c:483