0.5 release omissions

[Brian D. Carlstrom <bdc@martigny.ai.mit.edu>]

Franklin Chen writes:
 > scsh-0.5.0 is missing out-of-the-box support for a number of
 > platforms: signals1.c is not present in scsh/{cxux,irix,sunos,ultrix}.

We did a limited prerelease to people who did ports in the past and we
only got AIX. The authors only have access to BSD, HP-UX, and Solaris.

If anyone gets back to with addition signals1.c files we will crank
another release out.

-bri