This series of patches provides an implementation of the changes for C++
proposal P1423R3 [1].
These changes do not impact default libstdc++ behavior for C++17 and
earlier; they are only active for C++2a or when the -fchar8_t option is
specified.
Tested x86_64-linux.
Patch 1: Decouple constraints for u8path from path constructors.
Patch 2: Update __cpp_lib_char8_t feature test macro value, add deleted
operators, update u8path.
Patch 3: Updates to existing tests.
Patch 4: New tests.
Tom.
[1]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1423r3.html
