Properly calculate building requirements

In OH3 you can't build Capitol when Tavern is not builded.
In VCMI up to now you could.

client/windows/CCastleInterface.cpp

@@ -1378,7 +1378,7 @@ std::string CBuildWindow::getTextForState(int state)
 			};
 
 			ret = CGI->generaltexth->allTexts[52];
-			ret += "\n" + town->genBuildingRequirements(building->bid, false).toString(toStr);
+			ret += "\n" + town->genBuildingRequirements(building->bid).toString(toStr);
 			break;
 		}
 	case EBuildingState::MISSING_BASE:

lib/mapObjects/CGTownInstance.cpp

@@ -1126,7 +1126,7 @@ bool CGTownInstance::hasBuilt(BuildingID buildingID) const
 	return vstd::contains(builtBuildings, buildingID);
 }
 
-CBuilding::TRequired CGTownInstance::genBuildingRequirements(BuildingID buildID, bool includeUpgrade) const
+CBuilding::TRequired CGTownInstance::genBuildingRequirements(BuildingID buildID) const
 {
 	const CBuilding * building = town->buildings.at(buildID);
 
@@ -1138,10 +1138,14 @@ CBuilding::TRequired CGTownInstance::genBuildingRequirements(BuildingID buildID,
 		if (!hasBuilt(id))
 			return id;
 
-		if (build->upgrade != BuildingID::NONE && !hasBuilt(build->upgrade))
-			return build->upgrade;
+		CBuilding::TRequired::OperatorAll requirements;
 
-		return build->requirements.morph(dependTest);
+		if (build->upgrade != BuildingID::NONE)
+			requirements.expressions.push_back(dependTest(build->upgrade));
+
+		requirements.expressions.push_back(build->requirements.morph(dependTest));
+
+		return requirements;
 	};
 
 	CBuilding::TRequired::OperatorAll requirements;
@@ -1149,9 +1153,7 @@ CBuilding::TRequired CGTownInstance::genBuildingRequirements(BuildingID buildID,
 	{
 		const CBuilding * upgr = town->buildings.at(building->upgrade);
 
-		if (includeUpgrade)
-			requirements.expressions.push_back(upgr->bid);
-		requirements.expressions.push_back(upgr->requirements.morph(dependTest));
+		requirements.expressions.push_back(dependTest(upgr->bid));
 	}
 	requirements.expressions.push_back(building->requirements.morph(dependTest));
 

lib/mapObjects/CGTownInstance.h

@@ -238,7 +238,7 @@ public:
 	bool armedGarrison() const; //true if town has creatures in garrison or garrisoned hero
 	int getTownLevel() const;
 
-	CBuilding::TRequired genBuildingRequirements(BuildingID build, bool includeUpgrade=true) const;
+	CBuilding::TRequired genBuildingRequirements(BuildingID build) const;
 
 	void mergeGarrisonOnSiege() const; // merge garrison into army of visiting hero
 	void removeCapitols (PlayerColor owner) const;