make endian.h expose unprefixed macros, functions in standard profile

the resolution of Austin Group issue #162 adds endian.h as a standard
header for future versions of the standard, making it no longer
acceptable for some of the functionality to be hidden behind
_BSD_SOURCE or _GNU_SOURCE. the definitions of the [lb]etoh{16,32,64}
function-like macros are kept conditional since they are alternate
names which the standard did not adopt.

include/endian.h

@@ -3,19 +3,19 @@
 
 #include <features.h>
 
-#define __PDP_ENDIAN 3412
+#define __NEED_uint16_t
+#define __NEED_uint32_t
+#define __NEED_uint64_t
 
 #include <bits/alltypes.h>
 
-#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define __PDP_ENDIAN 3412
 
 #define BIG_ENDIAN __BIG_ENDIAN
 #define LITTLE_ENDIAN __LITTLE_ENDIAN
 #define PDP_ENDIAN __PDP_ENDIAN
 #define BYTE_ORDER __BYTE_ORDER
 
-#include <stdint.h>
-
 static __inline uint16_t __bswap16(uint16_t __x)
 {
 	return __x<<8 | __x>>8;
@@ -34,43 +34,47 @@ static __inline uint64_t __bswap64(uint64_t __x)
 #if __BYTE_ORDER == __LITTLE_ENDIAN
 #define htobe16(x) __bswap16(x)
 #define be16toh(x) __bswap16(x)
-#define betoh16(x) __bswap16(x)
 #define htobe32(x) __bswap32(x)
 #define be32toh(x) __bswap32(x)
-#define betoh32(x) __bswap32(x)
 #define htobe64(x) __bswap64(x)
 #define be64toh(x) __bswap64(x)
-#define betoh64(x) __bswap64(x)
 #define htole16(x) (uint16_t)(x)
 #define le16toh(x) (uint16_t)(x)
-#define letoh16(x) (uint16_t)(x)
 #define htole32(x) (uint32_t)(x)
 #define le32toh(x) (uint32_t)(x)
-#define letoh32(x) (uint32_t)(x)
 #define htole64(x) (uint64_t)(x)
 #define le64toh(x) (uint64_t)(x)
-#define letoh64(x) (uint64_t)(x)
 #else
 #define htobe16(x) (uint16_t)(x)
 #define be16toh(x) (uint16_t)(x)
-#define betoh16(x) (uint16_t)(x)
 #define htobe32(x) (uint32_t)(x)
 #define be32toh(x) (uint32_t)(x)
-#define betoh32(x) (uint32_t)(x)
 #define htobe64(x) (uint64_t)(x)
 #define be64toh(x) (uint64_t)(x)
-#define betoh64(x) (uint64_t)(x)
 #define htole16(x) __bswap16(x)
 #define le16toh(x) __bswap16(x)
-#define letoh16(x) __bswap16(x)
 #define htole32(x) __bswap32(x)
 #define le32toh(x) __bswap32(x)
-#define letoh32(x) __bswap32(x)
 #define htole64(x) __bswap64(x)
 #define le64toh(x) __bswap64(x)
-#define letoh64(x) __bswap64(x)
 #endif
 
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define betoh16(x) __bswap16(x)
+#define betoh32(x) __bswap32(x)
+#define betoh64(x) __bswap64(x)
+#define letoh16(x) (uint16_t)(x)
+#define letoh32(x) (uint32_t)(x)
+#define letoh64(x) (uint64_t)(x)
+#else
+#define betoh16(x) (uint16_t)(x)
+#define betoh32(x) (uint32_t)(x)
+#define betoh64(x) (uint64_t)(x)
+#define letoh16(x) __bswap16(x)
+#define letoh32(x) __bswap32(x)
+#define letoh64(x) __bswap64(x)
+#endif
 #endif
 
 #endif