Index: config.lua
==================================================================
--- config.lua
+++ config.lua
@@ -201,20 +201,26 @@
 			if incdir then incdir = incdir .. incsfx end
 	end
 	libdir = libdir or (prefix .. '/lib'     .. libsfx)
 	incdir = incdir or (prefix .. '/include' .. incsfx)
 
-	local libstr = pkc '--libs-only-l' -- (--static is not reliable)
-	local libs = fb and fb.libs or {}
-	local linkstatic = locdep
-	if (not locdep) and libstr then
+	local libs, linkstatic, libstr
+	if fb and fb.libs then
+		libs = fb.libs
+		libstr = pkc('--libs-only-l', unpack(fb.libs))
+	else
 		libs = {}
-		for m in string.gmatch(libstr, '-l(%g+)') do
-			libs[#libs + 1] = m
+		libstr = pkc '--libs-only-l' -- (--static is not reliable)
+		linkstatic = locdep
+		if (not locdep) and libstr then
+			libs = {}
+			for m in string.gmatch(libstr, '-l(%g+)') do
+				libs[#libs + 1] = m
+			end
+		else
+			if #libs == 0 then libs = { name } end
 		end
-	else
-		if #libs == 0 then libs = { name } end
 	end
 
 	conf.pkg[name] = {
 		prefix = prefix;
 		libdir = libdir;

Index: default.nix
==================================================================
--- default.nix
+++ default.nix
@@ -1,13 +1,12 @@
 let pkg = import <nixpkgs> {};
 in {stdenv          ? pkg.stdenv,
 	fetchFromGitHub ? pkg.fetchFromGitHub,
 	terra           ? pkg.terra,
-	pkgconfig       ? pkg.pkgconfig,
-	json_c          ? pkg.json_c,
+	pkg-config      ? pkg.pkg-config,
 	postgresql      ? pkg.postgresql.lib,
-	mbedtlsLegacy   ? pkg.mbedtls,
+	mbedtls         ? pkg.mbedtls,
 	glibc           ? pkg.glibc,
 	cmark           ? pkg.cmark,
 	inkscape        ? pkg.inkscape,
 	mongoose        ? null,
 	lib             ? pkg.lib,
@@ -21,35 +20,25 @@
 				rev = "369f44adfa38e0d8fa9667e9d6bafd7e0e3c6231";
 				sha256 = "17rkd7ydic39cw9sfh11mcil02vmi6jjyj2ncbxan6psak09xbrc";
 			};
 	pkv = val: p: "parsav_pkg_${p}_${val}";
 	pkp = pkv "prefix";
-	mbedtls = mbedtlsLegacy.overrideAttrs(o: rec{
-		version = "3.0-dev";
-		nativeBuildInputs = o.nativeBuildInputs ++ [pypkgs.jinja2];
-		src = fetchFromGitHub {
-			owner = "ARMmbed"; repo = "mbedtls";
-			rev = "49e9fbd6bc7c970c221be6e35f6872762ddde0bc";
-			sha256 = "1ips4mx8rr0kcqn7vdapx2m9xh4cayb7isbwvr98qp2ybi4pi4ai";
-		};
-	});
 in stdenv.mkDerivation {
 	name = "parsav";
 	version = "dev";
-	nativeBuildInputs = [terra json_c pkgconfig mbedtls];
+	nativeBuildInputs = [terra pkg-config mbedtls];
 	buildInputs = [cmark inkscape postgresql postgresql.lib];
 	src = ./.;
 
 	dontStrip = debug;
 	dbg = if debug then 1 else null;
 
-	${pkp "json-c"} = "${json_c}";
 	${pkp "mbedtls"} = "${mbedtls}";
 	${pkp "libc"} = "${glibc.out}";
 	${pkp "cmark"} = "${cmark}";
 	${pkp "inkscape"} = "${inkscape}";
-	${pkv "incdir" "libpq"} = "${postgresql.out}/include";
+	${pkv "incdir" "libpq"} = "${postgresql.dev}/include";
 	${pkv "libdir" "libpq"} = "${postgresql.lib}/lib";
 
 	parsav_build_branch = "trunk";
 	parsav_build_checkout = "<latest>";
 	parsav_builder = "nixpkgs";
@@ -69,9 +58,9 @@
 	# '';
 	
 	meta = {
 		description = "lightweight fediverse server";
 		homepage = https://c.hale.su/parsav;
-		license = lib.licenses.agpl3;
+		license = lib.licenses.agpl3Only;
 		platforms = lib.platforms.unix;
 	};
 } 

Index: pkgdata.lua
==================================================================
--- pkgdata.lua
+++ pkgdata.lua
@@ -3,14 +3,12 @@
 
 return {
 	mbedtls = { 
 		libs = {'mbedtls', 'mbedcrypto', 'mbedx509'};
 		osvars = {
-			linux_nixos = { -- lacks a *.pc on nixos systems
-				-- prefix = sthunk('nix', 'path-info', 'nixos.mbedtls');
-				prefix = os.getenv("parsav_pkg_mbedtls_prefix");
-			}
+			-- used to lack a *.pc on nixos systems
+			linux_nixos = { prefix = os.getenv("parsav_pkg_mbedtls_prefix"); }
 		};
 		vars = { builddir = '/library', srcincdir = '/include' };
 	};
 	mongoose = { vars = { builddir = '' } };
 	mjson = { vars = { builddir = '', srcincdir = '/src' } };