patch to clean up generic signum.h

[Zack Weinberg]

On Mon, 2 Nov 1998 17:27:05 -0500, Roland McGrath wrote:
>I think it is not "compulsive" but broken to omit signal numbers under
>_POSIX_SOURCE.  A POSIX.1-compliant program must define _POSIX_SOURCE,
>and a well-written one would handle common non-POSIX signals by checking
>for them with #ifdef.  

The only things I put under __USE_MISC were the obsolete names SIGIOT
and SIGCLD.

I did condition the POSIX signals on __USE_POSIX, which will affect
programs compiled with -ansi and nothing else that look for other
signals.  If you think that's broken, it can be changed.

zw