[Issue 22598] importC: Add support for __extension__ keyword

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=22598

--- Comment #5 from Walter Bright <bugzi...@digitalmars.com> ---
Once the `__extension__({ ... })` is parsed, what should the compiler do with
it?

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