gssdp_1_6: disable manpages

Building these doesn't make sense, because the only tool they are
available for - is disabled already. Building them is pointless.

This reduces rebuilds for pandoc / haskell-updates by up to 5k on Linux.

pkgs/development/libraries/gssdp/1.6.nix

@@ -7,8 +7,6 @@
   pkg-config,
   gobject-introspection,
   vala,
-  buildPackages,
-  enableManpages ? buildPackages.pandoc.compiler.bootstrapAvailable,
   gi-docgen,
   python3,
   libsoup_3,
@@ -44,8 +42,7 @@ stdenv.mkDerivation (finalAttrs: {
     vala
     gi-docgen
     python3
-  ]
-  ++ lib.optionals enableManpages [ buildPackages.pandoc ];
+  ];
 
   buildInputs = [
     libsoup_3
@@ -58,7 +55,8 @@ stdenv.mkDerivation (finalAttrs: {
   mesonFlags = [
     "-Dgtk_doc=true"
     "-Dsniffer=false"
-    (lib.mesonBool "manpages" enableManpages)
+    # This packages only has manpages for gssdp-device-sniffer, which we disabled above.
+    "-Dmanpages=false"
   ];
 
   # On Darwin: Failed to bind socket, Operation not permitted