[Issue 21938] importC: Support __attribute__ specifiers that could be mapped to D attributes

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21938

--- Comment #3 from Walter Bright <bugzilla at digitalmars.com> ---
Some of them:

https://github.com/dlang/dmd/pull/15048

https://github.com/dlang/dmd/pull/15047

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