diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index de150dceca..3498eadf0b 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -75,6 +75,7 @@ LDADDS = \
 	$(top_builddir)/gtk/libgtk-3.la	\
 	$(top_builddir)/gdk/libgdk-3.la	\
 	$(GTK_DEP_LIBS)				\
+	$(GDK_DEP_LIBS)			\
 	-lm
 
 bin_PROGRAMS = gtk3-demo gtk3-demo-application
diff --git a/tests/Makefile.am b/tests/Makefile.am
index b6a60996c5..d0eabaec91 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -18,6 +18,7 @@ LDADD = \
 	$(top_builddir)/gtk/libgtk-3.la	\
 	$(top_builddir)/gdk/libgdk-3.la	\
 	$(GTK_DEP_LIBS)			\
+	$(GDK_DEP_LIBS)			\
 	-lm
 
 if USE_X11