[Evolution-hackers] Heads Up: Widespread dependency changes in 2.31.4

[Matthew Barnes <mbarnes redhat com>]

GNOME 2.31.4 will be making the leap from gtk+-2.0 to gtk+-3.0, and that
means we have to follow suit in Evolution 2.31.4.

This contradicts our usual policy of only depending on stable libraries
so you can always build the latest development release on a stable GNOME
platform.  But being on the cusp of the GNOME 2 to GNOME 3 transition,
some disruption is to be expected.  We will return to our normal policy
after GNOME 3.0 is released and the next development cycle begins.

I debated whether to support both gtk+-2.0 and gtk+-3.0 simultaneously,
since other smaller GTK-based projects are attempting this, but decided
against it because it would double the number of possible configuration
permutations we'd now have to support: all existing permutations with
gtk+-2.0 + all existing permutations with gtk+-3.0.  That will lead to
more confusion and more bugs, which we have enough of as is.

If someone wants to take ownership of adding and -supporting- gtk+-2.0
backward compatibility, I'll be happy to review patches.  But officially
we're moving on.