diff --git a/shared/nm-glib-aux/nm-glib.h b/shared/nm-glib-aux/nm-glib.h
index 4043ec2240..93513a964f 100644
--- a/shared/nm-glib-aux/nm-glib.h
+++ b/shared/nm-glib-aux/nm-glib.h
@@ -569,9 +569,9 @@ _nm_g_value_unset (GValue *value)
 
 /*****************************************************************************/
 
-#if !GLIB_CHECK_VERSION (2, 57, 2)
+/* G_SOURCE_FUNC was added in 2.57.2. */
+#undef G_SOURCE_FUNC
 #define G_SOURCE_FUNC(f) ((GSourceFunc) (void (*)(void)) (f))
-#endif
 
 /*****************************************************************************/