Added zero size check to Xinerama sanity check.
Added zero size check to Xinerama sanity check.

darcs-hash:20060919070014-4eba8-aea63f8ffc5d9bbd8497d0c3968c8ebab6cb5e09.gz

dkogan/notion,knixeur/notion,anoduck/notion,dkogan/notion.xfttest,raboof/notion,knixeur/notion,neg-serg/notion,raboof/notion,knixeur/notion,knixeur/notion,p5n/notion,neg-serg/notion,dkogan/notion.xfttest,dkogan/notion,p5n/notion,anoduck/notion,dkogan/notion,anoduck/notion,p5n/notion,anoduck/notion,dkogan/notion.xfttest,anoduck/notion,p5n/notion,raboof/notion,dkogan/notion,neg-serg/notion,neg-serg/notion,dkogan/notion,p5n/notion,knixeur/notion,raboof/notion,dkogan/notion.xfttest