maintainer-feedback requested: [Bug 280791] textproc/zxing-cpp: fix build with libc++ 19

[bugzilla-noreply at freebsd.org]

Bugzilla Automation <bugzilla at FreeBSD.org> has asked freebsd-kde (group)
<kde at FreeBSD.org> for maintainer-feedback:
Bug 280791: textproc/zxing-cpp: fix build with libc++ 19
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=280791



--- Description ---
As noted in the libc++ 19 release notes [1], std::char_traits<> is now
only provided for char, char8_t, char16_t, char32_t and wchar_t, and any
instantiation for other types will fail.

This causes textproc/zxing-cpp to fail to compile with clang 19 and
libc++ 19, resulting in errors similar to:

    /usr/include/c++/v1/string_view:300:42: error: implicit instantiation of
undefined template 'std::char_traits<unsigned char>'
      300 |   static_assert(is_same<_CharT, typename
traits_type::char_type>::value,
	  |					     ^
   
/wrkdirs/usr/ports/textproc/zxing-cpp/work/zxing-cpp-2.2.1/core/src/Utf.cpp:72:
42:
note: in instantiation of template class 'std::basic_string_view<unsigned
char>' requested here
       72 | static size_t Utf8CountCodePoints(utf8_t utf8)
	  |					     ^
    /usr/include/c++/v1/__string/char_traits.h:45:8: note: template is declared
here
       45 | struct char_traits;
	  |	   ^

`utf8_t` is effectively defined as `std::basic_string<uint8_t>`, which
is no longer possible. So redefine it as a `std::vector<uint8_t>`
instead.

This requires only a small adjustment in one other place: replacing the
initializer list in the `AppendFromUtf8` call in `FromUtf8`.

[1] https://libcxx.llvm.org/ReleaseNotes/19.html#deprecations-and-removals