qbs: add optional support for cmake_file_name property

[ABBAPOH]

As was requested by user migrating from Conan 1.x here https://bugreports.qt.io/projects/QBS/issues/QBS-1849.

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[memsharded]

Thanks for your contribution @ABBAPOH

I am a bit confused about reusing the cmake_file_name property, as it is intended for CMake. If the qbs files need to differ from the package name, maybe it would be better to define a qbs_file_name new property? Because there are many cmake_file_name defined out there, that would change the qbs file name, who guarantees that the qbs file name is always aligned with the CMake one? I think it might not be the case, am I missing something?

[memsharded]

Same as above, probably no need of new setter/getter, and the QBSDeps.set_property() is the way to go

[memsharded]

Probably no need of the new argument, if we are going to use properties, maybe the approach should be similar to CMakeDeps and allow a local QBSDeps.set_property() that can override the upstream property, and also allows defining the property locally. This would be general for any property that the generator might use in the future too.

[ABBAPOH]

I think it might not be the case, am I missing something?

A user specifically asked for usage of cmake_file_name rather than the normal flow (pkg_config_name or dep.ref.name). My understanding is that they relied on cmake_file_name from Conan 1.x JSON generator and ask this feature to ease transition to Conan 2.x. It is indeed quite a daunting task to replace all entries Depends { name: "crashpad" } with Depends { name: "sentry-crashpad" } all over the project.
I am personally not fond of this feature, but I can see the reason - setting a single flag in the generator to use CMake names is much easier than replacing multiple dependencies across the project.

[memsharded]

I am not sure if I understand.

Conan 1 never used the cmake_file_name in any of the qbs generators, not the legacy qbs one, not in QbsProfile.
The JSON generator didn't serialize properties like cmake_file_name either: https://docs.conan.io/1/reference/generators/json.html. Then, this doesn't make sense from the migration point of view.

And even if that was the case, it is simply too incorrect to depend on a cmake_xxxx property for a qbs generator, unless the Qbs build system explicitly documented some kind of convention over CMake based open source libraries, which doesn't seem the case either.

So this would only make sense as a qbs_file_name property or something like that.