Why I'm not able to add properties to the collision modifier?

I want to add a simple flag to the structure “CollisionModifierData” within the header “DNA_modifier_types.h” and add a bool controlled in python through a new property in the file “rna_modifier.c”.
But the RNA code is not being generated (errors in compiling). Why?

Thanks in advance


For DNA changes the structs need to aligned so that there are no gaps, which can be done by adding some padding variables.


        float time_x, time_xnew;    /* cfra time of modifier */
+       char flag, pad[7];
        struct BVHTree *bvhtree;    /* bounding volume hierarchy for this cloth object */