Re: [PATCH] unit-tests: do show relative file paths on non-Windows, too

> There are compilers other than Visual C that want to show absolute
> paths.  Generalize the helper introduced by a2c5e294 (unit-tests: do
> show relative file paths, 2023-09-25) so that it can also work with
> a path that uses slash as the directory separator, and becomes
> almost no-op once one-time preparation finds out that we are using a
> compiler that already gives relative paths.  Incidentally, this also
> should do the right thing on Windows with a compiler that shows
> relative paths but with backslash as the directory separator (if
> such a thing exists and is used to build git).
> 
> Reported-by: Randall S. Becker <rsbecker@nexbridge.com>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
> 
>   * Another change I made, which is not described in the proposed
>     commit log message, is that we now use fspathcmp() instead of
>     strcmp() to precompute the prefix length using a known needle[]
>     string, to be consistent with the runtime check done for each and
>     every path.
> 
>     This is a belated follow-up on <f0b804129e8a21449cbb6f346473d3570182ddfa.1695640837.git.gitgitgadget@gmail.com>

> +		/*
> +		 * prefix_len == 0 if the compiler gives paths relative
> +		 * to the root of the working tree.  Otherwise, we want
> +		 * to see that we did find the needle[] at a directory
> +		 * boundary.
> +		 */
> +		if (fspathcmp(needle, prefix + prefix_len) ||
> +		    (prefix_len &&
> +		     prefix[prefix_len - 1] != '/' &&
> +		     prefix[prefix_len - 1] != '\\'))