--- libev/ev.c	2012/02/22 01:53:00	1.412
+++ libev/ev.c	2012/03/23 19:06:08	1.413
@@ -603,6 +603,8 @@
     #define ECB_MEMORY_FENCE         __machine_rw_barrier ()
     #define ECB_MEMORY_FENCE_ACQUIRE __machine_r_barrier  ()
     #define ECB_MEMORY_FENCE_RELEASE __machine_w_barrier  ()
+  #elif __xlC__
+    #define ECB_MEMORY_FENCE         __lwsync ()
   #endif
 #endif