"not-const" qualifier for C

Motivation sample:
struct X {
      const char* const type;
};
struct X * make_x(){
   struct X * p = malloc(sizeof *p);
   if (p)
   {
       p->type = strdup("X");  // *** error, type is const ***
       if (p->type == NULL)
       {
          free(p);
          p = NULL;
       }
   }
   return p; //ok
}
void print(struct X * p){
   prinf("%s", p->type);
}
void x_destroy(struct X * p)
{
    free(p->type); // *** warning const to non-const ***
}
Now consider we have the keyword "mutable" that removes const from struct members.
struct X {
      const char* const type;
};
struct X * make_x(){
   mutable struct X * p = malloc(sizeof *p);
   if (p)
   {
       p->type = strdup("X");  //OK
       if (p->type == NULL)
       {
          free(p);
          p = NULL;
       }
   }
   return p; //ok
}
void print(struct X * p){
   prinf("%s", p->type);
}
void x_destroy(mutable struct X * p)
{
    free(p->type); //no warning
}