include/compiler.h: typedef ulong for FreeBSD

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

include/compiler.h

@@ -44,7 +44,7 @@
 #ifdef __linux__
 # include <endian.h>
 # include <byteswap.h>
-#elif defined(__MACH__)
+#elif defined(__MACH__) || defined(__FreeBSD__)
 # include <machine/endian.h>
 typedef unsigned long ulong;
 #endif