[CMake] Variable Propagation

[C. Meissa]

Hello list,

A varible ${var1} can be accessed in any subdirectory’s 
CMakeLists.txt.
However, if those files change ${var1} these changes are not 
accessible from the directory above.

Is there any possibility of getting this done, anyway?
I need to provide easy adding for source files to the developers,
So it would be nice to just have a CMakelists.txt in every subfolder,
which then edits the source-variable.

Thanks so much.
C.M.