endian.h: add BSD convertions between big/little-endian byte order

This patch adds support for convertion of values between host and
big-/little-endian byte order.

Signed-off-by: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

include/endian.h

@@ -55,4 +55,42 @@
 # define __LONG_LONG_PAIR(HI, LO) HI, LO
 #endif
 
+
+#ifdef __USE_BSD
+/* Conversion interfaces.  */
+# include <byteswap.h>
+
+# if __BYTE_ORDER == __LITTLE_ENDIAN
+#  define htobe16(x) __bswap_16 (x)
+#  define htole16(x) (x)
+#  define be16toh(x) __bswap_16 (x)
+#  define le16toh(x) (x)
+
+#  define htobe32(x) __bswap_32 (x)
+#  define htole32(x) (x)
+#  define be32toh(x) __bswap_32 (x)
+#  define le32toh(x) (x)
+
+#  define htobe64(x) __bswap_64 (x)
+#  define htole64(x) (x)
+#  define be64toh(x) __bswap_64 (x)
+#  define le64toh(x) (x)
+# else
+#  define htobe16(x) (x)
+#  define htole16(x) __bswap_16 (x)
+#  define be16toh(x) (x)
+#  define le16toh(x) __bswap_16 (x)
+
+#  define htobe32(x) (x)
+#  define htole32(x) __bswap_32 (x)
+#  define be32toh(x) (x)
+#  define le32toh(x) __bswap_32 (x)
+
+#  define htobe64(x) (x)
+#  define htole64(x) __bswap_64 (x)
+#  define be64toh(x) (x)
+#  define le64toh(x) __bswap_64 (x)
+# endif
+#endif
+
 #endif	/* endian.h */