[Inkscape-devel] Warning fix for our libcroco copy

To the libcroco-copy maintainer,

Please have a look at rev. 13173, in which I fixed a number of compiler warnings.

There were some unused function arguments, and the "fix" was to assign a value to them but not use them, triggering a GCC warning. Plus it's confusing code, so I applied the "proper" fix by using a common "UNUSED" macro. Ugly, but that's C for you ;)

Cheers, Johan