diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 022a5da..abc022d 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -7315,6 +7315,7 @@
 gui_gnome		Compiled with Gnome support (gui_gtk is also defined).
 gui_gtk			Compiled with GTK+ GUI (any version).
 gui_gtk2		Compiled with GTK+ 2 GUI (gui_gtk is also defined).
+gui_gtk3		Compiled with GTK+ 3 GUI (gui_gtk is also defined).
 gui_mac			Compiled with Macintosh GUI.
 gui_motif		Compiled with Motif GUI.
 gui_photon		Compiled with Photon GUI.