Build transcript (DragonFly guest, /root) — exact commands, untrimmed:

$ cd /root && cc -O2 -Wall -o df4560 df4560_harness.c
(no diagnostics — clean build)
$ echo $?
0

Compiler: cc 8.3 [DragonFly] Release/2019-02-22 (/usr/bin/cc)
Host: DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 x86_64 (see env.txt)
Source integrity: cksum 1652572199 6642 matches the packed df4560_harness.c