Turns out this is a duplicate of 22403.
*** This issue has been marked as a duplicate of issue 22403 ***
Comment #2 by dlang-bot — 2021-10-19T09:58:27Z
dlang/dmd pull request #13185 "fix Issue 22403 - importC: Error: cannot pass argument '0' of type 'int' to parameter 'const(char)*'" was merged into stable:
- c3bfd18fbbcae6527879a3c1d051f34260b68136 by Iain Buclaw:
fix Issue 22404 - importC: Error: cannot pass argument 'ENUMMEM' of type 'int' to parameter '__tag2'
https://github.com/dlang/dmd/pull/13185