[CMake] Modification of a variable in a CMakeLists called with add_subdirectory

[Olivier Pierard]

Hi,

I'm facing another rather simple problem.

I try to modify a variable defined in the main CMakeLists.txt within
another one called by the add_subdirectory command.  Modification is
well taken into account in the subfolder but once back in the main one,
variable is set back to its previous value.  Is there a way to avoid
this behavior ?

Thanks for your help,

Olivier