Make lib imports in overlay explicit

overlay.nix

@@ -1,15 +1,19 @@
 final: /* Future last stage */
 prev:  /* Previous stage */
 
-with final.lib;
-
 let
-  callPackage = final.callPackage;
+  inherit (prev.lib) collect isDerivation mapAttrs;
+
+  inherit (final) callPackage;
 
   mkDeps = name: pkgs: final.runCommand name { }
     "printf '%s\n' ${toString (collect (x: x ? outPath) pkgs)} > $out";
 
-  bscPkgs = {
+  mkStrict = drv: if (isDerivation drv && drv ? overrideAttrs && !(drv ? strictDeps))
+    then drv.overrideAttrs { strictDeps = true; }
+    else drv;
+
+  bscPkgs = mapAttrs (_: mkStrict) {
     bench6 = callPackage ./pkgs/bench6/default.nix { };
     bigotes = callPackage ./pkgs/bigotes/default.nix { };
     clangOmpss2 = callPackage ./pkgs/llvm-ompss2/default.nix { };