Failed on 10.3-amd64 with
use of undeclared identifier 'O_CLOEXEC'
#define _GNU_SOURCE 1 does not help
I removed 'O_CLOEXEC' from line 308 in emulators/qemu-user-static/work/qemu-bsd-user-ec807d10/bsd-user/freebsd/os-proc.c.
(don't know if it is the right solution).
Huh ... this didn't happen on any of my poudriere jails when I built it. I'll regress and see what's up.
*** This bug has been marked as a duplicate of bug 214484 ***