Add fetchGitMirror function

overlay.nix

@@ -1,9 +1,8 @@
 final: /* Future last stage */
 prev:  /* Previous stage */
 
-with final.lib;
-
 let
+  lib = prev.lib;
   callPackage = final.callPackage;
 
   bscPkgs = {
@@ -98,19 +97,22 @@ let
     };
   };
 
+  # Load our custom lib functions with import, callPackage fails.
+  lib' = import ./pkgs/lib.nix { lib = prev.lib; };
+
   # For now, only build toplevel packages in CI/Hydra
-  pkgsTopLevel = filterAttrs (_: isDerivation) bscPkgs;
+  pkgsTopLevel = lib.filterAttrs (_: lib.isDerivation) bscPkgs;
 
   # Native build in that platform doesn't imply cross build works
   canCrossCompile = platform: default: pkg:
-    (isDerivation pkg) &&
+    (lib.isDerivation pkg) &&
     # If meta.cross is undefined, use default
     (pkg.meta.cross or default) &&
-    (meta.availableOn final.pkgsCross.${platform}.stdenv.hostPlatform pkg);
+    (lib.meta.availableOn final.pkgsCross.${platform}.stdenv.hostPlatform pkg);
 
   # For now only RISC-V
-  crossSet = genAttrs [ "riscv64" ] (platform:
-    filterAttrs (_: canCrossCompile platform true)
+  crossSet = lib.genAttrs [ "riscv64" ] (platform:
+    lib.filterAttrs (_: canCrossCompile platform true)
       final.pkgsCross.${platform}.bsc.pkgsTopLevel);
 
   buildList = name: paths:
@@ -126,21 +128,17 @@ let
     '';
 
   pkgsList = buildList "ci-pkgs" (builtins.attrValues pkgsTopLevel);
-  testsList = buildList "ci-tests" (collect isDerivation tests);
+  testsList = buildList "ci-tests" (lib.collect lib.isDerivation tests);
   allList = buildList' "ci-all" [ pkgsList testsList ];
   # For now only RISC-V
   crossList = buildList "ci-cross"
-    (filter
+    (lib.filter
       (canCrossCompile "riscv64" false) # opt-in (pkgs with: meta.cross = true)
         (builtins.attrValues crossSet.riscv64));
 
 in bscPkgs // {
 
-  lib = prev.lib // {
-    maintainers = prev.lib.maintainers // {
-      bsc = import ./pkgs/maintainers.nix;
-    };
-  };
+  lib = lib';
 
   # Prevent accidental usage of bsc-ci attribute
   bsc-ci = throw "the bsc-ci attribute is deprecated, use bsc.ci";