diff --git a/src/ngircd/io.c b/src/ngircd/io.c
index 9ffdfd6..9484b0b 100644
--- a/src/ngircd/io.c
+++ b/src/ngircd/io.c
@@ -86,6 +86,18 @@ static int io_masterfd;
 
 static int io_dispatch_kqueue(struct timeval *tv);
 static bool io_event_change_kqueue(int, short, const int action);
+
+#ifndef EV_SET
+#define EV_SET(kevp, a, b, c, d, e, f) do {     \
+        struct kevent *__kevp__ = (kevp);       \
+        __kevp__->ident = (a);                  \
+        __kevp__->filter = (b);                 \
+        __kevp__->flags = (c);                  \
+        __kevp__->fflags = (d);                 \
+        __kevp__->data = (e);                   \
+        __kevp__->udata = (f);                  \
+} while(0)
+#endif
 #endif
 
 #ifdef IO_USE_POLL