Fix build for OSX

Change-Id: I580a500edcf4812e570be586890abef746083a8c
Reviewed-on: https://gerrit.osmocom.org/74
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
diff --git a/include/osmocom/core/endian.h b/include/osmocom/core/endian.h
index c890fd7..02c6406 100644
--- a/include/osmocom/core/endian.h
+++ b/include/osmocom/core/endian.h
@@ -23,6 +23,17 @@
         #else
                 #error "Unknown endian"
         #endif
+#elif defined(__APPLE__)
+#include <machine/endian.h>
+	#if defined(__DARWIN_LITTLE_ENDIAN)
+		#define OSMO_IS_LITTLE_ENDIAN		1
+		#define OSMO_IS_BIG_ENDIAN		0
+	#elif define(__DARWIN_BIG_ENDIAN)
+		#define OSMO_IS_LITTLE_ENDIAN		0
+		#define OSMO_IS_BIG_ENDIAN		1
+	#else
+		#error "Unknown endian"
+	#endif
 #else
 #include <endian.h>
         #if __BYTE_ORDER == __LITTLE_ENDIAN