[PATCH STABLE] pager: set MORE=FRX on OS X and FreeBSD

[Jun Wu]

Excerpts from Augie Fackler's message of 2017-04-21 21:02:31 -0400:
> The vision I had for this was that packages would specify a sane pager for
> their platform in /etc/mercurial/pager.rc or something. I'm opposed to
> this patch, because it's putting the OS-specific preferences in Mercurial
> instead of in the packaging where it belongs.

The problem is, do you think "HGRCPATH=/dev/null hg log" needs to have a
sane behavior or not?

If not, we can make setup.py put some platform dependent files in default.d
to provide a good default if package maintainers forget. default.d configs
will be overridden by system config.