Adding cjdns.

The executable runs; I haven't tried to run a node.

pkgs/tools/networking/cjdns/default.nix

@@ -0,0 +1,31 @@
+{ stdenv, fetchgit, cmake }:
+
+let
+  rev = "f7b02ac0cc";
+in
+stdenv.mkDerivation {
+  name = "cjdns-git-20130620-${rev}";
+
+  src = fetchgit {
+    url = "https://github.com/cjdelisle/cjdns.git";
+    inherit rev;
+    sha256 = "1580a62yhph62nv7q2jdqrbkyk9a9g5i17snibkxyykc7rili5zq";
+  };
+
+  preConfigure = ''
+    sed -i -e '/toolchain.*CACHE/d' CMakeLists.txt
+  '';
+
+  doCheck = true;
+  checkPhase = "ctest";
+
+  buildInputs = [ cmake ];
+
+  meta = {
+    homepage = https://github.com/cjdelisle/cjdns;
+    description = "Encrypted networking for regular people";
+    license = "GPLv3+";
+    maintainers = with stdenv.lib.maintainers; [viric];
+    platforms = with stdenv.lib.platforms; linux;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -593,6 +593,8 @@ let
 
   chrony = callPackage ../tools/networking/chrony { };
 
+  cjdns = callPackage ../tools/networking/cjdns { };
+
   cksfv = callPackage ../tools/networking/cksfv { };
 
   ciopfs = callPackage ../tools/filesystems/ciopfs { };