Remove swap16/swap32/swap64 header pollution.

This seems to be obsolete BSD stuff, and the only references to it in the
tree are people #undef'ing it.

Bug: http://b/2735009
Change-Id: Icde523ae2d15cf1025357d861f97b415e89e4f9a

libc/include/byteswap.h

@@ -28,11 +28,10 @@
 #ifndef _BYTESWAP_H_
 #define _BYTESWAP_H_
 
-/* endian.h rather than sys/endian.h so we get the machine-specific file. */
-#include <endian.h>
+#include <sys/endian.h>
 
-#define  bswap_16(x)   swap16(x)
-#define  bswap_32(x)   swap32(x)
-#define  bswap_64(x)   swap64(x)
+#define bswap_16(x) __swap16(x)
+#define bswap_32(x) __swap32(x)
+#define bswap_64(x) __swap64(x)
 
 #endif /* _BYTESWAP_H_ */

libc/include/sys/endian.h

@@ -75,10 +75,6 @@ __END_DECLS
 #define	HTONL(x) (x) = htonl((u_int32_t)(x))
 #define	HTONS(x) (x) = htons((u_int16_t)(x))
 
-#define swap16 __swap16
-#define swap32 __swap32
-#define swap64 __swap64
-
 #define htobe16 __swap16
 #define htobe32 __swap32
 #define htobe64 __swap64