[ccache] ccache interrupt handling bug

[Tom Lane]

"Nadav Har'El" <nyh at cloudius-systems.com> writes:
> One thing you should perhaps consider is whether this change (using
> sigaction, signal sets, instead of the antique signal(), etc.) might break
> compilation on some antique UNIX machines or on MS-Windows (!?) or
> something. But I doubt any present-day system actually lacks sigaction()
> and friends, so I think your code is good.

Windows is definitely a risk factor here: AFAIK they don't provide a
decent emulation of the POSIX signal functions.  However, they don't
have the BSD ones either, so I assume ccache is already covering
Windows specially.

As for the "antique UNIX" angle, I can offer a data point: Postgres
still nominally carries support for the pre-POSIX signal API, but
AFAICT that code isn't being used on any platform still in use.
*All* of the active non-Windows members of our buildfarm report that
their configure test for POSIX signals succeeds.  And there are some
pretty darn old systems in there:
http://buildfarm.postgresql.org/cgi-bin/show_status.pl

			regards, tom lane