[MAJOR] implemented support for FreeBSD's kqueue() polling mechanism

It has not been tested yet, but at least it builds.
diff --git a/include/types/polling.h b/include/types/polling.h
index ed3cf64..81921ee 100644
--- a/include/types/polling.h
+++ b/include/types/polling.h
@@ -52,8 +52,9 @@
 #define POLL_USE_SELECT         (1<<0)
 #define POLL_USE_POLL           (1<<1)
 #define POLL_USE_EPOLL          (1<<2)
+#define POLL_USE_KQUEUE         (1<<3)
 
-extern int cfg_polling_mechanism;       /* POLL_USE_{SELECT|POLL|EPOLL} */
+extern int cfg_polling_mechanism;       /* POLL_USE_{SELECT|POLL|EPOLL|KQUEUE} */
 
 
 #endif /* _TYPES_POLLING_H */