mpvScripts.mpris: use patch sent upstream for make DESTDIR=

Make sure mpris.so is stripped.
mpv-with-scripts: use a standard location for scripts in $out.
mpvScripts.convert: install to the new location of mpv scripts.
Replaced gobject-introspection dependency with glib.

pkgs/applications/video/mpv/scripts/mpris.nix

@@ -1,7 +1,7 @@
-{ stdenv, fetchFromGitHub, pkgconfig, gobject-introspection, mpv }:
+{ stdenv, fetchpatch, fetchFromGitHub, pkgconfig, glib, mpv }:
 
 stdenv.mkDerivation rec {
-  name = "mpv-mpris-${version}.so";
+  pname = "mpv-mpris";
   version = "0.5";
 
   src = fetchFromGitHub {
@@ -10,14 +10,24 @@ stdenv.mkDerivation rec {
     rev = version;
     sha256 = "07p6li5z38pkfd40029ag2jqx917vyl3ng5p2i4v5a0af14slcnk";
   };
+  patches = [
+    # Enables to "make SCRIPTS_DIR=... install" https://github.com/hoyon/mpv-mpris/pull/38
+    (fetchpatch {
+      url = "https://github.com/hoyon/mpv-mpris/commit/f1482350868bf20e4575f923943ec998469b255e.patch";
+      sha256 = "1lqy867wpmj6hv3zgi6g679a7x3dv5skpw24hwd05b28galnyd4l";
+    })
+  ];
 
   nativeBuildInputs = [ pkgconfig ];
 
-  buildInputs = [ gobject-introspection mpv ];
+  buildInputs = [ glib mpv ];
 
-  installPhase = ''
-    cp mpris.so $out
-  '';
+  installFlags = [ "SCRIPTS_DIR=$(out)/share/mpv/scripts" ];
+
+  # Otherwise, the shared object isn't `strip`ped. See:
+  # https://discourse.nixos.org/t/debug-why-a-derivation-has-a-reference-to-gcc/7009
+  stripDebugList = [ "share/mpv/scripts" ];
+  passthru.scriptName = "mpris.so";
 
   meta = with stdenv.lib; {
     description = "MPRIS plugin for mpv";