clone and overrides

[Timothee Besset]

I'm trying to create a new cons environment from an existing one, and
modify some of the variables. I tried the following:

$vm_ta_env = $vm_env->clone(
  CFLAGS => '-DMISSIONPACK ' . $CFLAGS
  );

I end up with a $CFLAGS that only holds '-DMISSIONPACK ', I had to find
another way to get what I wanted:

%vm_ta_env_hash = $vm_env->copy();
$vm_ta_env_hash{CFLAGS} = '-DMISSIONPACK ' . $vm_ta_env_hash{CFLAGS};
$vm_ta_env = new cons(%vm_ta_env_hash);

Is there a reason why the clone() command doesn't override correctly? Or
is it a bug?

regards

TTimo