cleaned up BSWAP macros

# ifdef HAVE___BUILTIN_BSWAP32

#  define BSWAP16(x) __builtin_bswap32((x) << 16)

# else

#  define BSWAP16(x) ((((x)>>8) & 0xff) | (((x)<<8) & 0xff00))

#  define BSWAP16(x) ((((uint16_t)(x))>>8) | (((uint16_t)(x))<<8))

# endif

#endif

#ifdef HAVE___BUILTIN_BSWAP32

# define BSWAP32(x) __builtin_bswap32(x)

#else

# define BSWAP32(x) ((BSWAP16(x)<<16) | (BSWAP16((x)>>16)))

# define BSWAP32(x) ((((uint32_t)BSWAP16(x))<<16)|((uint32_t)BSWAP16((x)>>16)))

#endif

#ifdef HAVE___BUILTIN_BSWAP64

# define BSWAP64(x) __builtin_bswap64(x)

#else

# define BSWAP64(x) ((BSWAP32(x)<<32) | (BSWAP32((x)>>32)))

# define BSWAP64(x) ((((uint64_t)BSWAP32(x))<<32)|((uint64_t)BSWAP32((x)>>32)))

#endif

#if defined(BUGGY_LONG_LONG)