gnome3.totem: fix build

Hopefully a proper fix for https://github.com/orivej/nixpkgs/commit/be17bccf38a2e5a5701115e15adf7ed5c585ac7d

pkgs/desktops/gnome-3/core/totem/default.nix

@@ -15,11 +15,6 @@ stdenv.mkDerivation rec {
 
   doCheck = true;
 
-  # https://bugs.launchpad.net/ubuntu/+source/totem/+bug/1712021
-  # https://bugzilla.gnome.org/show_bug.cgi?id=784236
-  # https://github.com/mesonbuild/meson/issues/1994
-  enableParallelBuilding = false;
-
   NIX_CFLAGS_COMPILE = "-I${gnome3.glib.dev}/include/gio-unix-2.0";
 
   nativeBuildInputs = [ meson ninja vala pkgconfig intltool python3Packages.python itstool wrapGAppsHook ];
@@ -46,7 +41,13 @@ stdenv.mkDerivation rec {
     patchShebangs .
   '';
 
-  mesonFlags = [ "-Dwith-nautilusdir=lib/nautilus/extensions-3.0" ];
+  mesonFlags = [
+    "-Dwith-nautilusdir=lib/nautilus/extensions-3.0"
+    # https://bugs.launchpad.net/ubuntu/+source/totem/+bug/1712021
+    # https://bugzilla.gnome.org/show_bug.cgi?id=784236
+    # https://github.com/mesonbuild/meson/issues/1994
+    "-Denable-vala=no"
+  ];
 
   wrapPrefixVariables = [ "PYTHONPATH" ];