As I have problem on getting useful reports from Gammu/Wammu crashes, I realised that having debug package for Gammu is good idea. However looking into official documentation didn't reveal how to achieve this. The wiki seems also miss information about this. Well then it must be something obvious. Fortunately I'm not only one who didn't find it on first attempt and dinosaur already wrote about this.
However I still wonder why this didn't get to some official documentation. For now I wrote down this to wiki, so it is easier to find for anybody else.