crucible_points_to doesn't work with function return value of pointer type

[brianhuffman]

This issue applies to the crucible-integration branch of saw-script.

If we compile the following C file to LLVM bitcode

static int val = 3;
int *test() {
	return (&val);
}

and run the following saw-script command

crucible_llvm_verify "test" []
  do {
    ret <- crucible_execute_func [];
    crucible_points_to ret (crucible_term {{ 3:[32] }});
  };

then we get the following error

Non-pointer value in points-to assertion

even though the return value actually has pointer type.