Compiler test

[wusatosi]

Implement trivial cases for #73 .

By trivial I mean either available from package managers (GCC), or via officially supported install script (LLVM).

Included versions:

GCC:

• 14
• 13
• 12
  Note: Lower versions are generally available on apt. GCC 15 mentioned in Enable latest versions of compilers on main #73 is not available due to no official release.

LLVM:

• 20
• 19
• 18
• 17
  Note: Lower versions (Enable latest versions of compilers on main #73 requests 16) is not available from llvm's official script as it is no longer supported. See: apt.llvm.org repository for noble (ubuntu 24.04) only provides meta packages, can not install llvm/llvm-project#90536

This adds 7 new CI jobs.

As GCC/ Clang doesn't publish their nightly build on package managers, using nightly/ head of compiler will need us to build either a custom image or be tested in a nightly job.

Note: A more complicated but CI-wide salable approach using custom build docker image is being experimented.
Instead of pulling various versions of compiler on every CI run, we use a pre-built docker image that has all compilers install.
See: https://github.com/wusatosi/cpp-docker/ for an example of docker image, we can speed this up by having multiple kinds of image.
See: https://github.com/wusatosi/exemplar/tree/compiler-test-docker as a proof of concept on exemplar side implementation.
See: https://github.com/wusatosi/exemplar/actions/runs/12216494307/job/34079670273 as an example of actions run.

[steve-downey]

Don't do this to your own system, it will eventually corrupt your OS. However, for a throwaway VM like CI:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-15 g++-15

or something similar

The ubuntu-toolchain-r/test apt repo is the Ubuntu toolchain group's test repository.

[wusatosi]

Just out of curiosity, why would it break your os?

[steve-downey]

Not every time, and not immediately, but it replaces components with the test versions, and eventually gets something slightly wrong in such a way that apt can't generate a solution for normal updates and installs. You can generally recover by uninstalling everything and reinstalling without the PPA.

[wusatosi]

Don't do this to your own system, it will eventually corrupt your OS. However, for a throwaway VM like CI:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-15 g++-15

or something similar

The ubuntu-toolchain-r/test apt repo is the Ubuntu toolchain group's test repository.

Hum, I don't think its working.
Reports: E: Unable to locate package gcc-15

Maybe gcc-15 is not available on 24.04?

See: https://github.com/bemanproject/exemplar/actions/runs/12215966614/job/34078564865

[wusatosi]

@neatudarius this is requested by you, do you mind reviewing this PR?