Fix Firefox wrapper set-as-default functionality

pkgs/applications/networking/browsers/firefox/wrapper.nix

@@ -1,5 +1,5 @@
 { stdenv, lib, browser, makeDesktopItem, makeWrapper, plugins, gst_plugins, libs, gtk_modules
-, browserName, desktopName, nameSuffix, icon
+, browserName, desktopName, nameSuffix, icon, libtrick ? true
 }:
 
 let p = builtins.parseDrvName browser.name; in
@@ -33,7 +33,21 @@ stdenv.mkDerivation {
         --suffix-each GTK_PATH ':' "$gtk_modules" \
         --suffix-each LD_PRELOAD ':' "$(cat $(filterExisting $(addSuffix /extra-ld-preload $plugins)))" \
         --prefix GST_PLUGIN_SYSTEM_PATH : "$GST_PLUGIN_SYSTEM_PATH" \
-        --prefix-contents PATH ':' "$(filterExisting $(addSuffix /extra-bin-path $plugins))"
+        --prefix-contents PATH ':' "$(filterExisting $(addSuffix /extra-bin-path $plugins))" \
+        --set MOZ_OBJDIR "$(ls -d "${browser}/lib/${browserName}*")"
+
+    ${ lib.optionalString libtrick
+    ''
+    sed -e "s@exec @exec -a '$out/bin/${browserName}${nameSuffix}' @" -i "$out/bin/${browserName}${nameSuffix}"
+    libdirname="$(echo "${browser}/lib/${browserName}"*)"
+    libdirbasename="$(basename "$libdirname")"
+    mkdir -p "$out/lib/$libdirbasename"
+    ln -s "$libdirname"/* "$out/lib/$libdirbasename"
+    script_location="$(mktemp "$out/lib/$libdirbasename/${browserName}${nameSuffix}.XXXXXX")"
+    mv "$out/bin/${browserName}${nameSuffix}" "$script_location"
+    ln -s "$script_location" "$out/bin/${browserName}${nameSuffix}"
+    ''
+    }
 
     mkdir -p $out/share/applications
     cp $desktopItem/share/applications/* $out/share/applications

pkgs/top-level/all-packages.nix

@@ -11172,6 +11172,7 @@ let
     in
     import ../applications/networking/browsers/firefox/wrapper.nix {
       inherit stdenv lib makeWrapper makeDesktopItem browser browserName desktopName nameSuffix icon;
+      libtrick = true;
       plugins =
          assert !(enableGnash && enableAdobeFlash);
          assert !(jre && icedtea);