CMake -> Meson?

Meson is gaining popularity and we may think about using it for building and testing Batsim.
Many big projects are now using it as their main build system, so I do not think we will be blocked by missing features.

IMHO the main benefit would be an improved maintainability.

Pros

• Concise description.
• Well designed, consistent, default options are the ones desired (e.g., parallel build/test, enable warnings).
• Does not reimplement the wheel.
  • Use Ninja as main backend — therefore generates a good Ninja description file.
    Ninja is blazing fast. Dependencies between objects are finer grain than CMake ones.
    Incremental build is both saner and faster.
    (NB: CMake can use Ninja but not as well as Meson).
  • Uses external tool for dependency management (e.g., pkg-config). I believe this choice is good.
    Letting each project determining how it should be used (e.g., by providing a .pc file) is probably the best choice.
• It might be a way to escape the current test hell.
  (read test/robin if you do not know what I mean, or just ask @cmommess how easy it is to simply remove tests...)
  • Meson's syntax provides usable loops and data types, such as arrays and dictionaries!
  • Meson's testing system seems well designed (e.g., wrapping simple tests with valgrind or gdb is trivial)

Cons

• Less mature. Documentation is not perfect but seems to be enough for our use.
  (NB: CMake documentation is not great, but a lot of help can be found on stakoverflow-like sites).
• Having an up-to-date Meson may be hard on some systems such as NixOS.
• Some work is required to change our CMake stuff into something else.