LLVM OpenMP runtime

[sant0s12]

WIP Implementation of the LLVM OpenMP runtime.

Added initial implementation of the LLVM OpenMP runtime.

Added

• New KMP runtime.
• Runtime testing infrastructure.
• Automated benchmark running and plotting.
• Embedded Template Library.
• Clangd and clang-tidy configs.
• Banshee config.

Changed

• Snitch trace now includes the SP to aid in building better tracevis.
• The tracevis target now depends on the trace target and uses uses -cf.
• omp runtime directory renamed to gomp.
• Link with lld when using clang.

Fixed

• Fix building verilator on newer clang and gcc versions.
• Fix tracing targets missing some harts.
• Clang warnings about the .comment section.

Checklist

• [x] Automated tests pass
• [x] Changelog updated
• [x] Code style guideline is observed

Please check our contributing guidelines before opening a Pull Request.