Feature request: function prototypes

[Robert Fraser]

This may seem like a pretty stupid request, but since I use a lot of 
version() statements in my code; it'd be really cool to have something 
like function signatures at the top of my file. When I declare my 
versioned functions, I'd love to be able to have them checked against 
prototypes declared above their use, as a first line of defense (so I 
don't need to r-test it on different OSes and libraries if I make an 
obvious change to one of the signatures or something).