[CM] Snd 7.15

[andersvi at extern.uio.no]

Compiling snd-7/audio.c of recent snd-7 (as well as clm-3) breaks
with

  ...audio.c:8090: error: `SIGKILL' undeclared ...

putting in:

   #include <signal.h>

somewhere above seems to fix it here at least.