Bumping GLib Requirement for Pidgin3

[Michael McConville]

On Wed, Jun 17, 2015 at 10:39:31PM -0400, Ethan Blanton wrote:
> Jorge Villaseñor spake unto us the following wisdom:
> > Looking at https://developer.pidgin.im/wiki/Dependencies I would say
> > that for 3.0 we bump the glib version to 2.40 (included in RHEL 7)
> > and leave old versions of distributions to live with 2.x.y or
> > backport if they want to.
> 
> 2.40 would include Ubuntu LTS, Debian Jessie, and RHEL 7.  I have no
> problem with dropping support for long-term releases older than these.
> By the time Pidgin 3.0 is out, they will all be thoroughly established
> (Jessie is, to be fair, only a few days old!) and supported for many
> years to come.
> 
> I have no problem with this bump, particularly if there's anything in
> 2.40 that we want to use.  Whatever cruft we keep around now is likely
> to be with us for quite a while!

In my GSoC repo, I bumped the requirement in configure.ac:

	https://hg.pidgin.im/soc/2015/mmcc/main/rev/a14fae2791a2

And removed some preproc conditions:

	https://hg.pidgin.im/soc/2015/mmcc/main/rev/99eecd58690c

I'm looking at acinclude.m4 now.

I also removed GStreamer 0.10 support and a lot of related preproc
conditions. I'll clean up HAVE_FARSIGHT conditions and other V/V
conditions very soon.