quassel: Fix use of mkDerivation

The `with stdenv;` would override the `mkDerivation` to be the regular
one, instead of the libsForQt5 one.

This simply removes the dangerous use of the all-encompassing `with`,
and prefers using a more precise inherit for `lib`.

See #65399

Co-authored-by: worldofpeace <worldofpeace@protonmail.ch>

pkgs/applications/networking/irc/quassel/default.nix

@@ -5,7 +5,7 @@
 , static ? false # link statically
 
 , stdenv, fetchFromGitHub, cmake, makeWrapper, dconf
-, qtbase, qtscript
+, mkDerivation, qtbase, qtscript
 , phonon, libdbusmenu, qca-qt5
 
 , withKDE ? true # enable KDE integration
@@ -20,6 +20,7 @@
 }:
 
 let
+    inherit (stdenv) lib;
     buildClient = monolithic || client;
     buildCore = monolithic || enableDaemon;
 in
@@ -31,7 +32,7 @@ assert !buildClient -> !withKDE; # KDE is used by the client only
 let
   edf = flag: feature: [("-D" + feature + (if flag then "=ON" else "=OFF"))];
 
-in with stdenv; mkDerivation rec {
+in (if !buildClient then stdenv.mkDerivation else mkDerivation) rec {
   name = "quassel${tag}-${version}";
   version = "0.13.1";
 
@@ -67,12 +68,14 @@ in with stdenv; mkDerivation rec {
     ++ edf client "WANT_QTCLIENT"
     ++ edf withKDE "WITH_KDE";
 
-  preFixup =
+  dontWrapQtApps = true;
+
+  postFixup =
     lib.optionalString enableDaemon ''
       wrapProgram "$out/bin/quasselcore" --suffix PATH : "${qtbase.bin}/bin"
     '' +
     lib.optionalString buildClient ''
-        wrapProgram "$out/bin/quassel${lib.optionalString client "client"}" \
+      wrapQtApp "$out/bin/quassel${lib.optionalString client "client"}" \
         --prefix GIO_EXTRA_MODULES : "${dconf}/lib/gio/modules"
     '';