Add package for vlock from Debian mirror.

This is mainly because the original upstream URL is not available anymore.

svn path=/nixpkgs/trunk/; revision=34442

pkgs/misc/screensavers/vlock/default.nix

@@ -0,0 +1,22 @@
+{ stdenv, fetchurl, pam }:
+
+stdenv.mkDerivation {
+  name = "vlock-2.2.2";
+  src = fetchurl
+  {
+    url = mirror://debian/pool/main/v/vlock/vlock_2.2.2.orig.tar.gz;
+    sha256 = "1b9gv7hmlb8swda5bn40lp1yki8b8wv29vdnhcjqfl6ir98551za";
+  };
+
+  prePatch = ''
+    sed -i -e '/INSTALL/s/-[og] [^ ]*//g' Makefile modules/Makefile
+  '';
+
+  configureFlags = "VLOCK_GROUP=root ROOT_GROUP=root";
+
+  buildInputs = [ pam ];
+
+  meta = {
+    description = "Virtual console locking program";
+  };
+}

pkgs/top-level/all-packages.nix

@@ -4747,6 +4747,8 @@ let
     inherit (pkgs.pythonPackages) numpy;
   };
 
+  vlock = callPackage ../misc/screensavers/vlock { };
+
   vmime = callPackage ../development/libraries/vmime { };
 
   vrpn = callPackage ../development/libraries/vrpn { };