CMake defines package paths that are architecture dependent and architecture independent. The latter case is important for shipping Frameworks that are largely data with some CMake package definitions for depending on them in other projects (such as breeze-icon-theme).
In order to allow these modules to be able to install in the architecture-independent path, we need to define a common variable for this. That is now CMAKENOARCHPACKAGEDIR.
And to make this less confusing, the old one that assumed the architecture-specific path is deprecated and now defined by the new CMAKEARCHEDPACKAGEDIR variable.