Abigail pointed out how to fix the problem with prototypes. The other way is to not use prototypes. I went through a phase after I discovered them where I used prototypes everywhere. Then I discovered the problems that they can cause like this one.

The current wisdom is that prototypes should only be used where they are required and not just for checking arguments. One place they are required is to make functions work like Perl operators. Another case I just ran into is that mod_perl use prototypes to figure out which functions are handler methods.