--- acx-20070101/wlan_compat.h.orig	2006-05-20 20:27:57.000000000 +0200
+++ acx-20070101/wlan_compat.h	2009-08-28 18:52:52.000000000 +0200
@@ -221,8 +221,10 @@
 #ifndef IRQ_NONE
 #define IRQ_NONE
 #define IRQ_HANDLED
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 30)
 typedef void irqreturn_t;
 #endif
+#endif
 
 #ifndef ARPHRD_IEEE80211_PRISM
 #define ARPHRD_IEEE80211_PRISM 802