Minor optimization in dependency checking.
When reading the depend.internal file, check only once for every depender whether it exists, instead of repeatedly in a loop for each dependee. Within that function it can only change of the depender is removed. This is taken care of. This reduces the number of access() calls in kdelibs/khtml from 180000 to 90000 (i.e. 50%), and reduces the time for that (without the actual scanning) from 0.3 s to 0.21 s on my system. Alex