diff --git a/util-linux/volume_id/ext.c b/util-linux/volume_id/ext.c
index 9745106..a1a0808 100644
--- a/util-linux/volume_id/ext.c
+++ b/util-linux/volume_id/ext.c
@@ -18,6 +18,8 @@
  *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_EXT) += ext.o
+
 #include "volume_id_internal.h"
 #include "bb_e2fs_defs.h"