Core/Misc: Fix compile errors introduced in previous merge

There are probably other merge issues that got through, please report them

src/tools/map_extractor/System.cpp

@@ -901,7 +901,7 @@ bool ConvertADT(char *filename, char *filename2, int /*cell_y*/, int /*cell_x*/,
     {
         for (int j = 0; j < ADT_CELLS_PER_GRID; ++j)
         {
-            adt_MCNK * cell = cells->getMCNK(i,j);
+            adt_MCNK * cell = adt.cells[i][j];
             if (!cell)
                 continue;
             holes[i][j] = cell->holes;