=== DF-4502 / DF-4503 build on guest (DragonFly 6.5-DEVELOPMENT, X86_64_GENERIC) ===
$ cd /tmp && cc -O2 -Wall -o trigger_DF4502 DF4502.c
BUILD4502: OK
$ cc -O2 -Wall -o trigger_DF4503 DF4503.c
BUILD4503: OK
-rwxr-xr-x  1 root  wheel  7856 Sep 20 21:31 trigger_DF4502
-rwxr-xr-x  1 root  wheel  7832 Sep 20 21:31 trigger_DF4503
cc 8.3 [DragonFly] Release/2019-02-22
(earlier variant of trigger_DF4502.c that included <cam/cam.h> failed:
 "fatal error: cam/cam.h: No such file or directory" -- the clean-install
 guest ships no CAM userland headers; final version shells out to
 /sbin/camcontrol instead)