C++20 compatibility

[churley-qcom]

Summary

This PR updates SystemC-Components to support compilation with C++20, in addition to existing support for C++11, C++14, and C++17. The main change is a minimal, two-line update in scv_introspection.h to ensure compatibility with newer C++ standards.

Motivation

• C++20 support: Modern toolchains and projects are increasingly adopting C++20. Ensuring SystemC-Components builds and runs correctly with C++20 broadens its usability and future-proofs the codebase.
• Maintain backward compatibility: The change preserves support for C++11, C++14, and C++17.

Testing

• CI coverage: Added GitHub Actions CI to verify build and test success across C++11, C++14, C++17, and C++20 using an example program.
• Demonstration of issue:
  CI run showing failure on C++20 but passing on earlier standards.
• Demonstration of fix:
  CI run showing pass for all tested C++ versions after this change.

Dependency Updates

• LWTR4SC: Temporarily pointed .gitmodules to my fork (churley-qcom/LWTR4SC) with a pending PR (Minres/LWTR4SC#2) for C++20 compatibility.
• CCI: Updated the bundled CCI code to match the latest changes from the Accellera repo (commit 3f0b24d).

Code Change

• File: scv_introspection.h
• Change: Resolve C++20 parsing ambiguity with nested template names.

Impact

• No API changes.
• No behavioral changes.
• No new dependencies.

[churley-qcom]

@eyck, having a copy of CCI code in the SCC repo is not ideal. Can it be made a submodule instead?

[eyck]

Actually no since this copy contains modifications to make it working with Cadence Xcelium. Those changes will not be accepted to the Accellera report.
If you use provide CCI e.g. via a package manager the copy in SCC will not be used.

[eyck]

Now as the lwtr4sc PR is merged could you please change the submodule link back to the lwtr4sc repo?

[churley-qcom]

Actually no since this copy contains modifications to make it working with Cadence Xcelium. Those changes will not be accepted to the Accellera report. If you use provide CCI e.g. via a package manager the copy in SCC will not be used.

Ok thanks, that makes sense.

[churley-qcom]

Now as the lwtr4sc PR is merged could you please change the submodule link back to the lwtr4sc repo?

DONE and it's passing in the CI on my fork: https://github.com/churley-qcom/SystemC-Components/actions/runs/16060595888