jibri: add section to xorg conf file, for module

This change is adapted from a different jibri package, written by
@puckipedia for nixcon-video-infra 2020 along with a module for jibri.
Co-authored-by: Puck Meerburg <[e-mail]>

pkgs/servers/jibri/default.nix

···
-{ lib, stdenv, fetchurl, dpkg, jre_headless, makeWrapper }:
+{ lib, stdenv, fetchurl, dpkg, jre_headless, makeWrapper, writeText, xorg }:
+
+let
+  xorgModulePaths = writeText "module-paths" ''
+    Section "Files"
+      ModulePath "${xorg.xorgserver}/lib/xorg/modules
+      ModulePath "${xorg.xorgserver}/lib/xorg/extensions
+      ModulePath "${xorg.xorgserver}/lib/xorg/drivers
+      ModulePath "${xorg.xf86videodummy}/lib/xorg/modules/drivers
+    EndSection
+  '';
 
+in
 stdenv.mkDerivation rec {
   pname = "jibri";
   version = "8.0-93-g51fe7a2";
···
     mkdir -p $out/{bin,opt/jitsi/jibri,etc/jitsi/jibri}
     mv etc/jitsi/jibri/* $out/etc/jitsi/jibri/
     mv opt/jitsi/jibri/* $out/opt/jitsi/jibri/
+
+    cat '${xorgModulePaths}' >> $out/etc/jitsi/jibri/xorg-video-dummy.conf
 
     makeWrapper ${jre_headless}/bin/java $out/bin/jibri --add-flags "-jar $out/opt/jitsi/jibri/jibri.jar"