I think this is fine, but perhaps the prototypes should be `git__win32_path_utf8_to_16(git_win32_path_utf16 dest, const char *src)` and `git__win32_path_utf16_to_8(git_win32_path_utf8 dest, const wchar_t *src)` instead since the `src` buffers don't have to be of full array length (and in most cases are not, at least for the usage in src/win32/posix_w32.c).

So long as this isn't generating warnings on any of the platforms, I'm not worried about it though.