poudriere jail -c -j head -v head -a amd64 -m src=/usr/src

root@momh167-gjp4-8570p:~ # time poudriere jail -c -j head -v head -a amd64 -m src=/usr/src
[00:00:00] Creating head fs at /usr/local/poudriere/jails/head... done
[00:00:01] Copying /usr/src to /usr/local/poudriere/jails/head/usr/src... done
[00:08:14] Starting make installworld
--- installworld ---

…

awk: can't open file /sys/param.h
 source line number 1
[00:16:56] Recording filesystem state for clean... done
[00:16:57] Jail head 13.0-CURRENT 1300088 amd64 is ready to be used
296.244u 134.831s 16:56.78 42.3%        314+516k 301938+208357io 13320pf+0w
root@momh167-gjp4-8570p:~ #