Fatal: Conditionally compile the leak guard in caller namespace

Only compile the leak guard into the caller's namespace if the wrapper
sub is compiled into the namespace as well.

Signed-off-by: Niels Thykier <niels@thykier.net>
Fatal: Add lexical vs non-lexical CORE sub cache

Signed-off-by: Niels Thykier <niels@thykier.net>