Add 'third_party/nix/' from commit 'be66c7a6b24e3c3c6157fd37b86c7203d14acf10'

git-subtree-dir: third_party/nix
git-subtree-mainline: cf8cd640c1
git-subtree-split: be66c7a6b24e3c3c6157fd37b86c7203d14acf10

third_party/nix/tests/run.nix

@@ -0,0 +1,17 @@
+with import ./config.nix;
+
+{
+  hello = mkDerivation {
+    name = "hello";
+    buildCommand =
+      ''
+        mkdir -p $out/bin
+        cat > $out/bin/hello <<EOF
+        #! ${shell}
+        who=\$1
+        echo "Hello \''${who:-World} from $out/bin/hello"
+        EOF
+        chmod +x $out/bin/hello
+      '';
+  };
+}