[PATCH] xfsprogs: fix crc32 build on big endian

While kernelspace can test #ifdef __LITTLE_ENDIAN, this
doesn't work in userspace.  __LITTLE_ENDIAN is defined -
as is __BIG_ENDIAN.

So we build on all boxes as __LITTLE_ENDIAN, and the
self-test (thankfully!) fails on big endian boxes.

Fix this by testing __BYTE_ORDER values.

And add an else which should never be hit, but just in case...

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---

diff --git a/libxfs/crc32.c b/libxfs/crc32.c
index 1c0d958..0f847d2 100644
--- a/libxfs/crc32.c
+++ b/libxfs/crc32.c
@@ -63,18 +63,20 @@ typedef __u32	u64;
 static inline u32
 crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256])
 {
-# ifdef __LITTLE_ENDIAN
+#if __BYTE_ORDER == __LITTLE_ENDIAN
 #  define DO_CRC(x) crc = t0[(crc ^ (x)) & 255] ^ (crc >> 8)
 #  define DO_CRC4 (t3[(q) & 255] ^ t2[(q >> 8) & 255] ^ \
 		   t1[(q >> 16) & 255] ^ t0[(q >> 24) & 255])
 #  define DO_CRC8 (t7[(q) & 255] ^ t6[(q >> 8) & 255] ^ \
 		   t5[(q >> 16) & 255] ^ t4[(q >> 24) & 255])
-# else
+# elif __BYTE_ORDER == __BIG_ENDIAN
 #  define DO_CRC(x) crc = t0[((crc >> 24) ^ (x)) & 255] ^ (crc << 8)
 #  define DO_CRC4 (t0[(q) & 255] ^ t1[(q >> 8) & 255] ^ \
 		   t2[(q >> 16) & 255] ^ t3[(q >> 24) & 255])
 #  define DO_CRC8 (t4[(q) & 255] ^ t5[(q >> 8) & 255] ^ \
 		   t6[(q >> 16) & 255] ^ t7[(q >> 24) & 255])
+# else
+#  error What endian are you?
 # endif
 	const u32 *b;
 	size_t    rem_len;