During code generation process there is a list of tunable parameters with storage classes can this be automated?

Hi, I am trying to build a model from m-file and have been able to simulate it and build a subsystem. If I build manually(Generate the code) I get a list of tunable parameters before the build with inline storage class. I manually change it to imported extern for code generation. Can this process be done automated from a m file. The variables that are tunable are constant blocks in simulink and there values are being specified from matlab workspace.