Add C as a project language in CMake as a workaround

Due to a bug with LLVM 14 and greater it is necessary to add C as a project language.

added RTA label

added hlt1-throughput-decreased label

removed hlt1-throughput-decreased label

added Build label

assigned to @dcampora

By definition this cannot affect anything, but let's be double-sure.

/ci-test

added ci-test-triggered label

• [2023-03-03 18:10] Validation started with lhcb-master-mr#7215

resolved all threads

approved this merge request

unassigned @dcampora

merged

mentioned in commit f40f4700