patch 7.4.1402
Problem:    GTK 3 is not supported.
Solution:   Add GTK 3 support. (Kazunobu Kuriyama)
diff --git a/runtime/doc/gui.txt b/runtime/doc/gui.txt
index d779763..520eba9 100644
--- a/runtime/doc/gui.txt
+++ b/runtime/doc/gui.txt
@@ -25,7 +25,7 @@
 
 First you must make sure you actually have a version of Vim with the GUI code
 included.  You can check this with the ":version" command, it says "with xxx
-GUI", where "xxx" is X11-Motif, X11-Athena, Photon, GTK, GTK2, etc., or
+GUI", where "xxx" is X11-Motif, X11-Athena, Photon, GTK2, GTK3, etc., or
 "MS-Windows 32 bit GUI version".
 
 How to start the GUI depends on the system used.  Mostly you can run the
@@ -514,11 +514,14 @@
 This does require the |+menu| feature enabled at compile time.
 
 							*tear-off-menus*
-GTK+ and Motif support Tear-off menus.  These are sort of sticky menus or
+GTK+ 2 and Motif support Tear-off menus.  These are sort of sticky menus or
 pop-up menus that are present all the time.  If the resizing does not work
 correctly, this may be caused by using something like "Vim*geometry" in the
 defaults.  Use "Vim.geometry" instead.
 
+As to GTK+ 3, tear-off menus have been deprecated since GTK+ 3.4.
+Accordingly, they are disabled if gvim is linked against GTK+ 3.4 or later.
+
 The Win32 GUI version emulates Motif's tear-off menus.  Actually, a Motif user
 will spot the differences easily, but hopefully they're just as useful.  You
 can also use the |:tearoff| command together with |hidden-menus| to create
@@ -650,8 +653,8 @@
 The priority for the PopUp menu is not used.
 
 The Help menu will be placed on the far right side of the menu bar on systems
-which support this (Motif and GTK+).  For GTK+ 2, this is not done anymore
-because right-aligning the Help menu is now discouraged UI design.
+which support this (Motif and GTK+).  For GTK+ 2 and 3, this is not done
+anymore because right-aligning the Help menu is now discouraged UI design.
 
 You can use a priority higher than 9999, to make it go after the Help menu,
 but that is non-standard and is discouraged.  The highest possible priority is