Variables defined, (sometimes) assigned, and never used

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

When compiling with flag W=1 a lot of warnings about variables defined but 
never used show up. If one read the source sometimes it's clear that the 
original author placed them there because she/he wants to use the variable 
for doing something in a future release of the driver. I've also seen a 
comment like /* TODO */ near some unused variables. 

I thought to delete a couple of variables that are declared, may be also 
assigned as a result of some expression, but neither  used within a 
function or returned to the caller.

What to do with those (currently) unnecessary variables? Should we remove 
them or let everything as is?

Thanks,

Fabio