Index: sys/kern/kern_ffclock.c
===================================================================
--- sys/kern/kern_ffclock.c	(revision 227961)
+++ sys/kern/kern_ffclock.c	(working copy)
@@ -49,6 +49,8 @@
 
 #ifdef FFCLOCK
 
+FEATURE(ffclock, "Feed-forward clock support");
+
 extern struct ffclock_estimate ffclock_estimate;
 extern struct bintime ffclock_boottime;
 extern int8_t ffclock_updated;