[libcxxabi] [llvm] [libcxxabi][ItaniumDemangle] Demangle explicitly named object parameters (PR #72881)

[Michael Buch via llvm-commits]

Michael137 wrote:

The buildkite job for this PR is failing on Windows/Linux with:
```
.../llvm-project/github-pull-requests/llvm/include/llvm/Demangle/ItaniumDemangle.h:905:5: error: use of undeclared identifier 'DEMANGLE_ASSERT'
    DEMANGLE_ASSERT(
    ^
```

Pretty sure it isn't a problem with this patch. Is there some misconfiguration going on? (@ldionne)

https://github.com/llvm/llvm-project/pull/72881