Re: pgsql: Add PSQL_WATCH_PAGER for psql's \watch command.

Thomas Munro <tmunro@postgresql.org> writes:
> To make \watch react quickly when the user quits the pager or presses
> ^C, and also to increase the accuracy of its timing and decrease the
> rate of useless context switches, change the main loop of the \watch
> command to use sigwait() rather than a sleeping/polling loop, on Unix.

I think this is going to fall over on gaur, which doesn't have POSIX-style
sigwait.  We've escaped dealing with that so far because our only existing
use of sigwait is hidden under

#if defined(ENABLE_THREAD_SAFETY) && !defined(WIN32)

Perhaps the easiest answer is to make the #if conditional for this
code look like that too.

            regards, tom lane