build: Add cln-postgres package to nix flake

nix/checks/flake-module.nix

@@ -8,6 +8,7 @@
     {
       checks = {
         cln = config.packages.cln;
+        cln-postgres = config.packages.cln-postgres;
         rust = config.packages.rust;
         cargo-audit = pkgs.craneLib.cargoAudit {
           src = ../../.;

nix/pkgs/default.nix

@@ -3,6 +3,7 @@
   lib,
   pkgs,
   config,
+  postgresSupport ? false,
 }:
 with pkgs;
 let
@@ -32,6 +33,7 @@ stdenv.mkDerivation {
       automake
       gettext
       gitMinimal
+      postgresql
       libtool
       lowdown
       pkgconf
@@ -39,6 +41,7 @@ stdenv.mkDerivation {
       unzip
       which
     ]
+    ++ lib.optionals postgresSupport [ postgresql ]
     ++ lib.optionals stdenv.isDarwin [
       cctools
       darwin.autoSignDarwinBinariesHook

nix/pkgs/flake-module.nix

@@ -6,6 +6,10 @@
       packages = rec {
         # This package depends on git submodules so use a shell command like 'nix build .?submodules=1'.
         cln = pkgs.callPackage ./default.nix { inherit self pkgs config; };
+        cln-postgres = pkgs.callPackage ./default.nix {
+          inherit self pkgs config;
+          postgresSupport = true;
+        };
         rust = pkgs.callPackage ./rust.nix { craneLib = pkgs.craneLib; };
         default = cln;
       };

nix/shells.nix

@@ -10,6 +10,7 @@
     {
       devShells = {
         default = pkgs.mkShell { inputsFrom = [ config.packages.default ]; };
+        postgres = pkgs.mkShell { inputsFrom = [ config.packages.cln-postgres ]; };
         rust = pkgs.craneLib.devShell {
           checks = {
             inherit (self.checks.${system}) rust;