https://sourceforge.net/tracker/?func=detail&aid=1713606&group_id=154335&atid=791368
--- src/mod_cband.h.orig	2007-05-05 22:10:38.000000000 +0000
+++ src/mod_cband.h	2007-05-05 22:11:22.000000000 +0000
@@ -1,3 +1,4 @@
+
 /*
  * $Id: mod_cband.h,v 1.5 2006/05/28 18:58:37 dembol Exp $
  *
@@ -68,7 +69,7 @@
 #define CBAND_HANDLER_ALL		0
 #define CBAND_HANDLER_ME		1
 
-#if (defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)) || defined(__FreeBSD__)
+#if (defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)) || defined(__FreeBSD__) || defined(__APPLE_CC__)
 /* union semun is defined by including <sys/sem.h> */
 #else
 /* according to X/OPEN we have to define it ourselves */
