Can I create a global variable to use for future projects?

[Angew (Petr Kmoch)]

@johnratius

Yes, I am intending to use it with CMake only. Where would I declare this, so all CMake files have access to it? Would I need to configure it in the CMake GUI application?

You already have a solution, but just to answer your questions. I was talking about creating a system environment variable (similar to PATH). That is what CMake dereferences using the $ENV{var_name} syntax. The way to declare this depends on your operating system.