diff --git a/sys/conf/config.mk b/sys/conf/config.mk
--- a/sys/conf/config.mk
+++ b/sys/conf/config.mk
@@ -12,6 +12,9 @@
 	@echo "#define SMP 1" >> ${.TARGET}
 	@echo "#define MAC 1" >> ${.TARGET}
 	@echo "#define VIMAGE 1" >> ${.TARGET}
+.for _o in ${KERN_OPTS_EXTRA}
+	@echo "#define ${_o} 1" >> ${.TARGET}
+.endfor
 # Note: Define 'options' in DEFAULTS to 1. For simplicity, no check if the
 # option is in opt_global.h. Nearly all the options in DEFAUlTS today are in
 # opt_global.h with GEOM_* being the main exceptions. Move any options from