[Bug libstdc++/106749] Implement C++23 library features

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106749
Bug 106749 depends on bug 113318, which changed state.

Bug 113318 Summary: [C++23] Implement P1185R12, Naming text encodings to 
demystify them
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113318

           What    |Removed                     |Added
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             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED