[Bug c++/98940] Implement C++23 language features

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98940
Bug 98940 depends on bug 102616, which changed state.

Bug 102616 Summary: [C++23] P2334R1 - Add support for preprocessing directives 
elifdef and elifndef
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102616

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