This includes fixes and cleanups listed below:
- If a process dissappears while we are signalling it, don't count it as a
match/error.
- Better handling of errors and messages.
- Downgrade failure to kill(2) (other than ESRCH) from fatal error to a
warning; otherwise processing aborts and possibly matching killees would
remain unsignalled. This makes pkill match the Solaris behavior.
- Exit with 2 on usage errors as documented.
Obtained from: NetBSD
Glanced at by: maintainer (gad) [a bit different version of this patch]
53ff091d14