pidgin/pidgin

Merge release-2.x.y branch into main, with manual merges in
ChangeLog (easy)
Makefile.mingw (easy)
configure.ac (easy)
irc/msgs.c (not too bad)

And some Windows build files. We should make sure the pango used by 3.0.0
doesn't have the crash bug from CVE-2013-6486.
How to build Pidgin for Windows using MinGW
===========================================
For the latest build instructions, please refer to:
https://developer.pidgin.im/wiki/BuildingWinPidgin