Merge "Use as much of the macOS endian support as we can."

#else

/* Mac OS and Windows have nothing. */

#define __LITTLE_ENDIAN 1234

#if defined(__APPLE__)

/* macOS has some of the basics. */

#include <sys/_endian.h>

#else

/* Windows really has nothing. */

#define LITTLE_ENDIAN __LITTLE_ENDIAN

#define __BIG_ENDIAN 4321

#define BIG_ENDIAN __BIG_ENDIAN

#define __BYTE_ORDER __LITTLE_ENDIAN

#define BYTE_ORDER __BYTE_ORDER

#define htons(x) __builtin_bswap16(x)

#define htonl(x) __builtin_bswap32(x)

#define htonq(x) __builtin_bswap64(x)

#define ntohs(x) __builtin_bswap16(x)

#define ntohl(x) __builtin_bswap32(x)

#endif

/* Neither macOS nor Windows have the rest. */

#define __LITTLE_ENDIAN 1234

#define __BIG_ENDIAN 4321

#define __BYTE_ORDER __LITTLE_ENDIAN

#define htonq(x) __builtin_bswap64(x)

#define ntohq(x) __builtin_bswap64(x)

#define htobe16(x) __builtin_bswap16(x)