Fix issues in CI

[bjosv]

Fixes most remaining issues in CI (hopefully) to get most jobs green.

• Enable building non-cluster test on FreeBSD in CI
• Don't run tests on Windows in CI workflow "CI"
• CMake correction for libevent header.
• Update compilers in CI build matrix Use latest available gcc/clang in workflow "CI"
• Fix 32bit build in CI workflow "C/C++ CI"

Known issue left: ci.yml: Run static checkers - clang-format needed to make it happy. build.yml: Intermittent timing issue in test on macOS.

Then additional fixes are required, like updating Actions to remove Github warnings, and merging of CI jobs, some are redundant.. Other finding: PLATFORM_FLAGS is not set on built binaries i.e. tests.

[michael-grunder]

The macOS SSL_connect failure happens sporadically in hiredis as well so not related to this PR.