Add find_package in support files?

[sloriot]

Consistency is a great thing so having all packages handled similar is the best, though I think that all packages should have the find inside so that maintenance will be easier as well.

Originally posted by @albert-github in #9112 (comment)

[LOTUS9679]

Hi @sloriot, I am interested in working on this CMake consistency issue.

Could you point me to an example of a "support file" that currently handles the find_package correctly, and one that needs to be updated? I want to make sure I follow the intended pattern.

[atta-ullah01]

@sloriot I have a branch ready refactoring dependencies (Eigen3, TBB, OpenMesh, etc.). Before opening the PR, I wanted to confirm my implementation strategy for these scenarios:

1. Encapsulation & Components I have moved all find_package calls, COMPONENTS lists (e.g., for ITK), and set_package_properties inside the CGAL_X_support.cmake modules. The consumer knows nothing about the dependency details.
I noticed that across the repository, every usage of complex packages (like ITK) requested the exact same list of COMPONENTS
2. Complex Logic (e.g., LASLIB) For dependencies requiring compiler checks (like MSVC_VERSION for LASLIB), I moved that logic entirely into the support module. The module decides validity; the consumer just includes it.
3. Handling REQUIRED Dependencies I switched the support modules to always be QUIET and for required dependencies, I raised the error manually.

Does this align with your goals?