Set CMP0142 policy in package templates

[Nekto89]

New behavior fixes warnings for Xcode generator in case of using CMake >= 3.25 and conan 2.

Without this policy CMake passes inexisting subdirectories to linker.
"ld: warning: directory not found for option '-L/Users/user/.conan2/p/b/expatbf806472793ba/p/lib/Release'"
https://cmake.org/cmake/help/latest/policy/CMP0142.html

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• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[uilianries]

@Nekto89 Hello! Thank you for your suggestion. Have you talked to https://github.com/conan-io/conan/issues first? It sounds more a feature to be added in CMakeToolchain than a workaround to be added in CCI directly.

[Nekto89]

@Nekto89 Hello! Thank you for your suggestion. Have you talked to https://github.com/conan-io/conan/issues first? It sounds more a feature to be added in CMakeToolchain than a workaround to be added in CCI directly.

I did not. I've discovered that conan2 always adds lib directories to interface of cmake targets and there is no way to disable it. And CMake adds one more subdirectory for Xcode without this policy. I don't think that CMakeToolchain should control such CMake policies globally for user, because it may break some code.

[uilianries]

@Nekto89 Let me check with Conan team, maybe are can find a way.

[valgur]

Yeah, this would make more sense as a policy set by Conan automatically, since the layout of the package directory is managed by Conan anyway.

Edit: On second thought, it might conflict with existing projects that rely on this deprecated feature.