Do not detect byte-order using _BIG/_LITTLE_ENDIAN
These defines are present on some FreeBSD systems, regardless of
whether the system is big- or little- endian. This was causing the
FreeBSD CI to be incorrectly flagged as big-endian.
Resolves https://github.com/ziglang/zig/issues/11391
319b5cbce5Cody Tapscott committed on 4/12/2022, 6:14:33 PMparent04dd439