Optimize list intersection

util.nix

@@ -20,10 +20,7 @@ let
         [(take cnt l)] ++ chunksOf cnt (drop cnt l)
       else [];
     # same as intersectLists but takes an array of lists to intersect instead of just two
-    intersectManyLists = l: 
-      if length l == 0 then []
-      else if length l == 1 then head l
-      else intersectLists (head l) (intersectManyLists (tail l));
+    intersectManyLists = ll: foldr intersectLists (head ll) ll;
     # converts a boolean to a int (c style)
     boolToInt = b: if b then 1 else 0;
     # drops the last element of a list