unix: don't use alphasort in uv_fs_scandir()
unix: don't use alphasort in uv_fs_scandir()

alphasort() uses strcoll() in some libcs (notably glibc and musl) which
makes it locale-sensitive.

Replace it with a simple strcmp-based lexicographic comparison for
consistent behavior across platforms.

Remove the special-casing for OpenBSD.  It has been exporting function
prototypes conforming to POSIX.1-2008 since OpenBSD 5.3 and that was
released more than three years ago.

OS X 10.7 is now the only special case left.

Fixes: https://github.com/libuv/libuv/issues/1045
PR-URL: https://github.com/libuv/libuv/pull/1046
Reviewed-By: Santiago Gimeno <3f17e29e343c4cf8809fb0970d81d6d8ee88d6b3@gmail.com>
Reviewed-By: Saúl Ibarra Corretgé <8a7991f6950ea189abf159d6ec98d2fcc13dc5f6@gmail.com>

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