radiotray-ng: add libsoup_3 and glib-networking; fix runtime

gstreamer libgstsoup plugin dlopens libsoup_3 and requires
glib-networking to work. This change adds libsoup_3 and LD_LIBRARY_PATH
so the dlopen can locate libsoup_3.

pkgs/applications/audio/radiotray-ng/default.nix

@@ -17,7 +17,9 @@
 , libxdg_basedir
 , wxGTK
 # GStreamer
+, glib-networking
 , gst_all_1
+, libsoup_3
 # User-agent info
 , lsb-release
 # rt2rtng
@@ -58,6 +60,8 @@ stdenv.mkDerivation rec {
     libxdg_basedir
     lsb-release
     wxGTK
+    # for https gstreamer / libsoup
+    glib-networking
   ] ++ gstInputs
     ++ pythonInputs;
 
@@ -89,6 +93,8 @@ stdenv.mkDerivation rec {
   preFixup = ''
     gappsWrapperArgs+=(--suffix PATH : ${lib.makeBinPath [ dbus ]})
     wrapProgram $out/bin/rt2rtng --prefix PYTHONPATH : $PYTHONPATH
+    # for GStreamer
+    gappsWrapperArgs+=(--prefix LD_LIBRARY_PATH : "${lib.getLib libsoup_3}/lib")
   '';
 
   meta = with lib; {