BUILD/MINOR: haproxy DragonFlyBSD affinity build update.

sched_setaffinity supported by this platform.

(cherry picked from commit 2d0493af49fa2518bb53a260e0b04bc43d9683c3)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/haproxy.c b/src/haproxy.c
index 019cc57..5e0fb18 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -3427,7 +3427,7 @@
 			}
 			ret = cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1, sizeof(cpuset), &cpuset);
 		}
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__DragonFly__)
 			sched_setaffinity(0, sizeof(unsigned long), (void *)&global.cpu_map.proc[proc]);
 #endif
 #endif