Convert Perl reference-to-undef to NULL
Convert Perl reference-to-undef to NULL

After cloning a Perl interpreter, most Clownfish objects end up as
references to undef. Make sure they're converted to a NULL pointer.

rectang/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish