glib-networking: hardcode GSettings path to gnomeproxy module

So that this can be loaded from programs not depending on gsettings-desktop-schemas.

Currently, this patch is much uglier than it could be due to
https://gitlab.gnome.org/GNOME/glib/issues/1884

pkgs/development/libraries/glib-networking/default.nix

@@ -1,5 +1,6 @@
 { stdenv
 , fetchurl
+, substituteAll
 , meson
 , ninja
 , pkgconfig
@@ -22,6 +23,13 @@ stdenv.mkDerivation rec {
     sha256 = "1mfw44qpmwvz6yzj8c6spx6z357wrmkk15byrkc5byagd82860fm";
   };
 
+  patches = [
+    (substituteAll {
+      src = ./hardcode-gsettings.patch;
+      gds_gsettings_path = glib.getSchemaPath gsettings-desktop-schemas;
+    })
+  ];
+
   postPatch = ''
     chmod +x meson_post_install.py # patchShebangs requires executable file
     patchShebangs meson_post_install.py