[Bug libstdc++/116802] Symbol `is` (non-standard) is user inside the library.

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116802

--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The C++ standard has an index of names defined in the library (which includes
"is") and can be used to check which names are reserved for use by the library.