diff --git a/toolkit/system/gnome/Makefile.in b/toolkit/system/gnome/Makefile.in
index ee9970d193fd..bf94c34137d5 100644
--- a/toolkit/system/gnome/Makefile.in
+++ b/toolkit/system/gnome/Makefile.in
@@ -65,6 +65,7 @@ CPPSRCS = \
 	$(NULL)
 
 ifdef MOZ_ENABLE_LIBNOTIFY
+REQUIRES += thebes
 CPPSRCS += \
 	nsAlertsService.cpp \
 	nsAlertsIconListener.cpp \