OK, this is a bit more complex, so I took another approach.
I have tried to merge the function CvUnitAI::AI_cityAttack between K-Mod and Super Forts. For me, it compiles. So in this version of the CvUnitAI.cpp file attached, I reverted to Karadoc's code as well for the function CvUnitAI::AI_follow.
It means that we have to undo all the other changes as stated in my posts # 14, 16, 18 and 20 (I told you to keep notes...):
edit CvPlot.h, find AI_sumStrength and comment it out as per Karadoc.
edit CvUnitAI.h, find AI_cityAttack and replace the line as follows as per Karadoc:
bool AI_cityAttack(int iRange, int iOddsThreshold, int iFlags = 0, bool bFollow = false);
edit CvUnitAI.h again, find AI_finalOddsThreshold, comment it out as per Karadoc.
same file still, in the beginning, find bool AI_follow and put it back as per Karadoc:
//bool AI_follow();
bool AI_follow(bool bFirst = true); // K-Mod
// K-Mod
in CvUnit.h this time, find virtual bool AI_follow and put it back as per Karadoc:
//virtual bool AI_follow() = 0;
virtual bool AI_follow(bool bFirst = true) = 0; // K-Mod
Cross fingers...
EDIT: actually, the files CvUnit.h and CvUnitAI.h were correct as per attachments in your posts #7 and 8! You just need to revert back to the previous version of CvPlot.h which I don't have.