garlicd: add to index and check for error

The garlicd is now available under garlic.garlid and it requires the
extra-sandbox-path option to be properly set.

garlic/garlicd/default.nix

@@ -0,0 +1,28 @@
+{
+  stdenv
+, nix
+, garlicTool
+}:
+
+let
+  extraPath = "${garlicTool}:${nix}";
+in
+  stdenv.mkDerivation {
+    name = "garlicd";
+    preferLocalBuild = true;
+
+    phases = [ "unpackPhase" "installPhase" ];
+
+    src = ./garlicd;
+
+    unpackPhase = ''
+      cp $src garlicd
+    '';
+
+    installPhase = ''
+      substituteInPlace garlicd \
+        --replace @extraPath@ ${extraPath}
+      mkdir -p $out/bin
+      cp -a garlicd $out/bin
+    '';
+  }