gssdp_1_6: support cross compilation

pkgs/development/libraries/gssdp/1.6.nix

@@ -1,5 +1,6 @@
 { stdenv
 , lib
+, fetchpatch
 , fetchurl
 , meson
 , ninja
@@ -19,14 +20,26 @@ stdenv.mkDerivation rec {
   pname = "gssdp";
   version = "1.6.2";
 
-  outputs = [ "out" "dev" ]
-    ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [ "devdoc" ];
+  outputs = [ "out" "dev" "devdoc" ];
 
   src = fetchurl {
     url = "mirror://gnome/sources/gssdp/${lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
     sha256 = "QQs3be7O2YNrV/SI+ABS/koU+J4HWxzszyjlH0kPn7k=";
   };
 
+  patches = [
+    (fetchpatch {
+      # https://gitlab.gnome.org/GNOME/gssdp/-/merge_requests/11
+      name = "gi-docgen-as-native-dep.patch";
+      url = "https://gitlab.gnome.org/GNOME/gssdp/-/commit/db9d02c22005be7e5e81b43a3ab777250bd7b27b.diff";
+      hash = "sha256-Q2kwZlpNvSzIcMalrOm5lO5iFe+myS7J0S0vkcp10cw=";
+    })
+  ];
+
+  depsBuildBuild = [
+    pkg-config
+  ];
+
   nativeBuildInputs = [
     meson
     ninja
@@ -47,14 +60,13 @@ stdenv.mkDerivation rec {
   ];
 
   mesonFlags = [
-    "-Dgtk_doc=${lib.boolToString (stdenv.buildPlatform == stdenv.hostPlatform)}"
+    "-Dgtk_doc=true"
     "-Dsniffer=false"
-    "-Dintrospection=${lib.boolToString (stdenv.buildPlatform == stdenv.hostPlatform)}"
   ];
 
   doCheck = true;
 
-  postFixup = lib.optionalString (stdenv.buildPlatform == stdenv.hostPlatform) ''
+  postFixup = ''
     # Move developer documentation to devdoc output.
     # Cannot be in postInstall, otherwise _multioutDocs hook in preFixup will move right back.
     find -L "$out/share/doc" -type f -regex '.*\.devhelp2?' -print0 \