The __BYTE_ORDER__ define is provided by gcc (since ~v4.6), clang
(since ~v3.2) and icc (since ~16.0.3).
The __BYTE_ORDER and BYTE_ORDER macros are libc specific and are not
available on all supported platforms such as mingw.
Add support for the __BYTE_ORDER__ macro as a fallback.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>