diff --git a/ext/nio4r/extconf.rb b/ext/nio4r/extconf.rb
index 31a5a85..5daec99 100644
--- a/ext/nio4r/extconf.rb
+++ b/ext/nio4r/extconf.rb
@@ -14,7 +14,7 @@
 
 $defs << "-DEV_USE_SELECT" if have_header("sys/select.h")
 
-$defs << "-DEV_USE_POLL" if have_header("poll.h")
+$defs << "-DEV_USE_POLL" if have_type("port_event_t", "poll.h")
 
 $defs << "-DEV_USE_EPOLL" if have_header("sys/epoll.h")