[gtk+] Add a release note about RGBA visuals

[Matthias Clasen <matthiasc src gnome org>]

commit 79cf8cd598c04d976abb0a31daacff5a9abbf479
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 3 22:43:59 2014 -0500

    Add a release note about RGBA visuals

 README.in |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/README.in b/README.in
index 6c109db..2cc514c 100644
--- a/README.in
+++ b/README.in
@@ -97,6 +97,11 @@ Release notes for 3.12
   and borders. This may require some adjustments in applications that
   were making assumptions about containers never rendering backgrounds.
 
+* GTK+ is now choosing an RGBA visual for its windows by default if
+  one is available. This can cause problems for applications which make
+  assumptions about the default visual. You can set GDK_RGBA=0 in the
+  environment to force GTK+ to use the default X11 visual, as before.
+
 Release notes for 3.10
 ======================