Index: head/sys/amd64/cloudabi64/cloudabi64_sysvec.c
===================================================================
--- head/sys/amd64/cloudabi64/cloudabi64_sysvec.c
+++ head/sys/amd64/cloudabi64/cloudabi64_sysvec.c
@@ -34,6 +34,7 @@
 #include <sys/module.h>
 #include <sys/proc.h>
 #include <sys/smp.h>
+#include <sys/sysctl.h>
 #include <sys/sysent.h>
 #include <sys/systm.h>
 
@@ -272,3 +273,4 @@
 
 DECLARE_MODULE_TIED(cloudabi64, cloudabi64_module, SI_SUB_EXEC, SI_ORDER_ANY);
 MODULE_DEPEND(cloudabi64, cloudabi, 1, 1, 1);
+FEATURE(cloudabi64, "CloudABI 64bit support");