You can do the following for the first goto question:

#...
goto LABEL;

#...

LABEL:; #A plain ; is basically the NOP you are looking for.
use Module;
[download]

For the second case, do you actually need the do{}while(); form? That syntax guarantees that the code in the do{} runs once at the price you discovered. If running the code zero times would be ok or if prior code ensures that the while condition is always true for one iteration, just use the while(){} form.

--
$you = new YOU;
honk() if $you->love(perl)