ADDED   default.nix
Index: default.nix
==================================================================
--- default.nix
+++ default.nix
@@ -0,0 +1,45 @@
+let pkg = import <nixpkgs> {};
+in {stdenv          ? pkg.stdenv,
+	fetchFromGitHub ? pkg.fetchFromGitHub,
+	terra           ? pkg.terra-modern,
+	pkgconfig       ? pkg.pkgconfig,
+	json_c          ? pkg.json_c,
+	postgresql      ? pkg.postgresql.lib,
+	mbedtls         ? pkg.mbedtls,
+	mongoose        ? null
+}:
+let mgsrc = if mongoose != null then mongoose
+			else fetchFromGitHub {
+				owner = "cesanta";
+				repo = "mongoose";
+				rev = "369f44adfa38e0d8fa9667e9d6bafd7e0e3c6231";
+				sha256 = "17rkd7ydic39cw9sfh11mcil02vmi6jjyj2ncbxan6psak09xbrc";
+			};
+	pkv = val: p: "parsav_pkg_${p}_${val}";
+	pkp = pkv "prefix";
+in stdenv.mkDerivation {
+	name = "parsav";
+	version = "dev";
+	nativeBuildInputs = [terra json_c pkgconfig mbedtls];
+	src = ./.;
+
+	${pkp "json-c"} = "${json_c}";
+	${pkp "libpq"} = "${postgresql}";
+	${pkp "mbedtls"} = "${mbedtls}";
+
+	parsav_target_os = "linux";
+	parsav_dist = "nixos";
+	configurePhase = ''
+		cp -r ${mgsrc} lib/mongoose
+	'';
+	installPhase = ''
+		make prefix=$prefix install
+	'';
+	
+	meta = {
+		description = "lightweight fediverse server";
+		homepage = https://c.hale.su/parsav;
+		license = stdenv.lib.licenses.agpl3;
+		platforms = stdenv.lib.platforms.unix;
+	};
+}