devel/librevisa: fix build with libc++ 19
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 devel/librevisa to fail to compile with clang 19 and libc++
19, resulting in errors similar to:
/usr/include/c++/v1/string:820:42: error: implicit instantiation of undefined template 'std::char_traits<unsigned short>'
820 | static_assert(is_same<_CharT, typename traits_type::char_type>::value,
| ^
usb/usb_resource_creator.cpp:73:20: note: in instantiation of template class 'std::basic_string<unsigned short>' requested here
73 | usb_string serial;
| ^
/usr/include/c++/v1/__fwd/string.h:23:29: note: template is declared here
23 | struct _LIBCPP_TEMPLATE_VIS char_traits;
| ^These can be fixed by using char16_t instead of uint16_t for the
usb_string type.
[1] https://libcxx.llvm.org/ReleaseNotes/19.html#deprecations-and-removals
PR: 282165
MFH: 2024Q4
(cherry picked from commit df7422d81ae570a17b48662af9f20f464f12b076)