--exclude confusing

[lifeofguenter]

the way how --exclude is currently implemented (https://github.com/ruxkor/checkinstall/blob/master/checkinstall#L1674) is not fully straight forward:

checkinstall validates the list against -d and -f, which means the first checkinstall --exclude will always fail (since those files haven't been installed yet) - I suppose this is then more a functionality to avoid that subsequent runs won't overwrite existing files?

Would it be possible to have some feature that is based on the newfiles.tmp while excluding simple patterns, so we can get a little more control over the .deb creation process?