linux build fix

ixwebsocket/IXEventFd.h

@@ -28,10 +28,10 @@ namespace ix
         // happens between a control thread and a background thread, which is
         // blocked on select.
         int _fildes[2];
+#endif
 
         // Used to identify the read/write idx
         static const int kPipeReadIndex;
         static const int kPipeWriteIndex;
-#endif
     };
 }