diff -Nurd libical-0.44.ori/src/libical/icaltz-util.c libical-0.44/src/libical/icaltz-util.c
--- libical-0.44.ori/src/libical/icaltz-util.c	2009-09-26 23:38:51.000000000 -0300
+++ libical-0.44/src/libical/icaltz-util.c	2009-11-24 01:45:13.000000000 -0200
@@ -27,6 +27,9 @@
 
 #if defined(sun) && defined(__SVR4)
 #include <sys/byteorder.h>
+#elif defined(__APPLE__)
+#include <libkern/OSByteOrder.h>
+#define bswap_32 OSSwapBigToHostInt32
 #else
 # ifdef HAVE_BYTESWAP_H
 #  include <byteswap.h>