Fix endianness detection.

Index: src/base/detect.h
--- src/base/detect.h.orig
+++ src/base/detect.h
@@ -85,15 +85,15 @@
 
 /* use gcc endianness definitions when available */
 #if defined(__GNUC__) && !defined(__APPLE__) && !defined(__MINGW32__) && !defined(__sun)
-	#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
+	#if defined(__FreeBSD__) || defined(__NetBSD__)
 		#include <sys/endian.h>
 	#else
 		#include <endian.h>
 	#endif
 
-	#if __BYTE_ORDER == __LITTLE_ENDIAN
+	#if BYTE_ORDER == LITTLE_ENDIAN
 		#define CONF_ARCH_ENDIAN_LITTLE 1
-	#elif __BYTE_ORDER == __BIG_ENDIAN
+	#elif BYTE_ORDER == BIG_ENDIAN
 		#define CONF_ARCH_ENDIAN_BIG 1
 	#endif
 #endif
