tmux 3.3a has a behavior change, since reverted, that is incompatible
with this test. Unfortunately, tmux 3.3a has already made it into some
distributions, so the test has to be disabled when tmux 3.3a is encountered.
This uses the same utility function that mosh-client/mosh-server do.
This resolves portability issues with the 'locale' command.
This fixes OpenBSD 6.0 and probably Haiku builds.
Replace some blind timeouts with actual synchronization.
Improve performance on some slow tests.
Tweak some of the remaining timeouts.
This still isn't good enough to get 'make -j9 check'
working reliably on Cygwin for me; I think some Cygwin/
Windows scheduling issues remain.
Alex Chernyakhovsky