Recently WT-11894 was merged and then reverted as it caused a CI-blocker. The CI-blocker was a result of using static_assertions without a message which is only valid for C23+ and WiredTiger is only C11. However it wasn't caught by GCC so possibly there is something more going on. It was caught by the macOS 13 variant, which doesn't run in a PR or in the merge queue.

In order to reproduce the WT-11894 compiler the error the following had to be true:

1. Be on an ARM host that supports RCPC (this is true for our evergreen hosts)
2. Don't compile with TSAN
3. Compiler under clang

WiredTiger, it turns out, doesn't compile with Clang for ARM in any of its testing variants (except Mac), this represents a sizeable hole.

We should create a variant, similar to that of ! Ubuntu 20.04 Compilers for ARM, but the Ubuntu 20.04 Compilers task is special and runs on a custom variant ubuntu2004-wt-build designed to have older versions of clang and gcc. Presumably the same doesn't exist for ARM so it probably won't be as simple as creating a new variant and using the same task definition.

The definition of complete for this task is:

• Create a new variant which runs linux on ARM.
• Have it compile WiredTiger with both clang and gcc.
• Add it to the PR testing