[gtk+] Mention XDG Base Dir migration in README for 3.6

[Matthias Clasen <matthiasc src gnome org>]

commit 922b4040915ffa87d45a1af41291b8e7c347ea46
Author: William Jon McCann <jmccann redhat com>
Date:   Fri Apr 27 21:44:26 2012 -0400

    Mention XDG Base Dir migration in README for 3.6
    
    https://bugzilla.gnome.org/show_bug.cgi?id=646631

 README.in |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)
---
diff --git a/README.in b/README.in
index 8811835..9622de6 100644
--- a/README.in
+++ b/README.in
@@ -72,6 +72,24 @@ and attach the patch to that bug report.
 Patches should be in unified diff form. (The -up option to GNU diff.)
 
 
+Release notes for 3.6
+=====================
+
+* Now follows the XDG Base Directory specification for user
+  configuration and data files. In detail,
+  * $XDG_CONFIG_HOME/gtk-3.0/custom-papers is the new location
+    for $HOME/.gtk-custom-papers
+  * $XDG_CONFIG_HOME/gtk-3.0/bookmarks is the new location
+    for $HOME/.gtk-bookmarks
+  * $XDG_DATA_HOME/themes is preferred over $HOME/.themes
+  * $XDG_DATA_HOME/icons is preferred over $HOME/.icons.
+  Existing files from the old location will still be read
+  if the new location does not exist.
+
+* $HOME/.gtk-3.0 is no longer in the default module load path.
+  If you want to load modules from there, add it to the GTK_PATH
+  environment variable.
+
 Release notes for 3.4
 =====================