Added libPackages

shell-modules/default.nix

@@ -32,9 +32,12 @@ in
             };
           }).config;
         recUpdate = nixpkgs.lib.recursiveUpdate;
+        libPackages = evaluated.libPackages pkgs;
         shell = recUpdate {
-          env = evaluated.env;
-          packages = evaluated.packages ++ (evaluated.extraPackages pkgs);
+          env = evaluated.env // {
+            LD_LIBRARY_PATH = (nixpkgs.lib.mkIf (libPackages != [ ]) (nixpkgs.lib.makeLibraryPath libPackages));
+          };
+          packages = evaluated.packages ++ (evaluated.extraPackages pkgs) ++ libPackages;
         } evaluated.override;
       in
       {

shell-modules/shell.nix

@@ -24,6 +24,16 @@ with lib;
       description = "Extra packages to install";
     };
 
+    libPackages = mkOption {
+      type = types.functionTo (types.listOf types.package) // {
+        merge =
+          loc: defs: p:
+          lib.concatMap (def: (def.value p)) defs;
+      };
+      default = p: [ ];
+      description = "Packages to install and add to library path";
+    };
+
     override = mkOption {
       type = types.attrs;
       default = { };