build: Add support for CMake builds

[gulfemsavrun]

1. Add a root CMakeLists.txt file to provide cross-platform build support, making it easier to link against OpenCSD in large external projects.

2. Generate native CMake package files using OpenCSDConfig.cmake.in template.

[mikel-armbb]

Hi,
I've tried out the cmake patch you provided on linux initially. It works in as far as it goes. However the lack of building the .so files etc for linux is an issue - any build update needs to be comprehensive and produce the same output per platform as the original build process.

The cmake install method installs far more header files than the linux install - at present the linux install only adds sufficient for using the c-api based library. There is also no uninstall option within the cmake solution

In short, what you have provided may be sufficient for build into a larger project - adding cmake to the library should also allow a standalone build that produces the same results as the existing build.

Regards

Mike

[mikel-armbb]

I've added an update on top of your original patch. Please look at and see if your requirements are still met.

I do not think this is yet tested enough for the main upstream branch so may have to miss the next release.

Mike

[gulfemsavrun]

I've added an update on top of your original patch. Please look at and see if your requirements are still met.

I do not think this is yet tested enough for the main upstream branch so may have to miss the next release.

Mike

Thanks for the feedback, Mike! I have just pushed a new commit that addresses your points regarding restricted header installation and the addition of the uninstall target. I have verified that these changes work on macOS, Linux, and Windows.

Can you please clarify where exactly you pushed an update on top of my patch, as I was not able to find it in the PR commits or branches?