[Bug c++/110338] Implement C++26 language features

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110338
Bug 110338 depends on bug 115745, which changed state.

Bug 115745 Summary: [C++26] P0963R3 - Structured binding declaration as a condition
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115745

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