[PATCH] compat/bswap.h: don't assume MSVC is little-endian

From: Daniel Gurney <dgurney99@gmail.com>
Date: Nov 11, 2020, 08:32 UTC
Message-ID: <20201111083227.605518-1-dgurney99@gmail.com>

In 1af265f0 (compat/bswap.h: simplify MSVC endianness detection, 2020-11-08) we attempted to simplify code by assuming MSVC builds will be for little-endian machines, since only unusably old versions of MSVC supported big-endian MIPS and m68k architectures.

However, it's possible that MSVC could be ported to build for a big-endian architecture again, so the simplification wasn't as future-proof as hoped.

So let's go back to the old way of detecting MSVC, and then checking architecture from a list of little-endian architecture macros.

Note that MSVC does not treat ARM64 as bi-endian, so we can safely treat it as little-endian.

Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Daniel Gurney <dgurney99@gmail.com>
---
 compat/bswap.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/bswap.h b/compat/bswap.h
index 72f225eaa8..512f6f4b99 100644
--- a/compat/bswap.h
+++ b/compat/bswap.h
@@ -74,7 +74,7 @@ static inline uint64_t git_bswap64(uint64_t x)
 }
 #endif
 
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM64))
 
 #include <stdlib.h>

-- 
2.29.2