Move overlays.nix to common

common/main.nix

@@ -5,6 +5,7 @@
     ./boot.nix
     ./fs.nix
     ./hw.nix
+    ./overlays.nix
     ./users.nix
   ];
 

common/overlays.nix

@@ -0,0 +1,25 @@
+{ options, ... }:
+
+let
+
+  bscpkgsSrc = builtins.fetchTarball "https://pm.bsc.es/gitlab/rarias/bscpkgs/-/archive/master/bscpkgs-master.tar.gz";
+  bscpkgs = import "${bscpkgsSrc}/overlay.nix";
+
+  xeon07Overlay = (self: super: {
+    slurm = super.bsc.slurm-16-05-8-1;
+  });
+
+in
+
+{
+  nix.nixPath =
+    # Prepend default nixPath values.
+    options.nix.nixPath.default ++
+    # Append our nixpkgs-overlays.
+    [ "nixpkgs-overlays=/etc/nixos/overlays-compat/" ]
+  ;
+
+  nixpkgs.overlays = [
+    bscpkgs xeon07Overlay
+  ];
+}