diff -urp ipw2100-1.1.0/ieee80211.h ipw2100-1.1.0-is_multicast_ether_addr/ieee80211.h
--- ipw2100-1.1.0/ieee80211.h	2005-03-14 17:54:24.000000000 +0100
+++ ipw2100-1.1.0-is_multicast_ether_addr/ieee80211.h	2005-06-18 11:15:43.000000000 +0200
@@ -643,10 +643,12 @@ enum ieee80211_state {
 #define MAC_ARG(x) ((u8*)(x))[0],((u8*)(x))[1],((u8*)(x))[2],((u8*)(x))[3],((u8*)(x))[4],((u8*)(x))[5]
 
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,12)
 extern inline int is_multicast_ether_addr(const u8 *addr)
 {
 	return ((addr[0] != 0xff) && (0x01 & addr[0]));
 }
+#endif
 
 extern inline int is_broadcast_ether_addr(const u8 *addr)
 {
Only in ipw2100-1.1.0-is_multicast_ether_addr: ieee80211.h.orig