Events: fixed test building with eventport on OS X.

Broken in d17f0584006f (1.9.13).

src/event/modules/ngx_eventport_module.c

diff --git a/src/event/modules/ngx_eventport_module.c b/src/event/modules/ngx_eventport_module.c
index 9184547..cc9aadc 100644
--- a/src/event/modules/ngx_eventport_module.c
+++ b/src/event/modules/ngx_eventport_module.c
@@ -49,7 +49,7 @@
     void       *portnfy_user;   /* user defined */
 } port_notify_t;
 
-#if (__FreeBSD__) && (__FreeBSD_version < 700005)
+#if (__FreeBSD__ && __FreeBSD_version < 700005) || (NGX_DARWIN)
 
 typedef struct itimerspec {     /* definition per POSIX.4 */
     struct timespec it_interval;/* timer period */