gstreamer: 1.14.4 -> 1.15.1, and extended gst-plugins-bad.

During the 1.14 -> 1.15 upgrade, lots of stuff stopped working because
gstreamer changed what features are enabled by default and which ones are
automatically turned on/off via pkgconfig dependency detection.

This resulted in the `gstreamer` ("core" attribute in nixpkgs) package
to have only 15 of its previous 163 build targets enabled, and downstream
packages breaking correspondingly.

To ease maintainability and to ensure users will find the expected features
available (and when not, will see in the nix file why not), we now pass
the `-Dauto_features=enabled` Meson build flag to all gstreamer builds,
which sets all `auto` dependencies to `enabled`, and we explicitly disable
those that we can't build.

This means in particular that `gst-plugins-bad` now has vastly more integrations
(namely all for which nixpkgs has libraries available).

pkgs/development/libraries/gstreamer/good/default.nix

@@ -10,6 +10,10 @@
 , libXext
 , libXfixes
 , ncurses
+, xorg
+, libgudev
+, wavpack
+, jack2
 }:
 
 assert gtkSupport -> gtk3 != null;
@@ -19,7 +23,7 @@ let
 in
 stdenv.mkDerivation rec {
   name = "gst-plugins-good-${version}";
-  version = "1.14.4";
+  version = "1.15.1";
 
   meta = with stdenv.lib; {
     description = "Gstreamer Good Plugins";
@@ -36,7 +40,7 @@ stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "${meta.homepage}/src/gst-plugins-good/${name}.tar.xz";
-    sha256 = "0y89qynb4b6fry3h43z1r99qslmi3m8xhlq0i5baq2nbc0r5b2sz";
+    sha256 = "15f6klr7wg6jlcyx0qspi13s8wmc9fij1bx1bbvy90a9a72v97rb";
   };
 
   outputs = [ "out" "dev" ];
@@ -58,10 +62,27 @@ stdenv.mkDerivation rec {
     libXext # present feature but undeclared in meson_options.txt, see https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/issues/553
     libXfixes # present feature but undeclared in meson_options.txt, see https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/issues/553
     ncurses
+    xorg.libXfixes # present feature but undeclared in meson_options.txt, see https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/issues/553
+    xorg.libXdamage # present feature but undeclared in meson_options.txt, see https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/issues/553
+    wavpack
   ]
   ++ optional gtkSupport gtk3 # for gtksink
   ++ optionals stdenv.isDarwin [ darwin.apple_sdk.frameworks.Cocoa ]
-  ++ optionals stdenv.isLinux [ libv4l libpulseaudio libavc1394 libiec61883 ];
+  ++ optionals stdenv.isLinux [ libv4l libpulseaudio libavc1394 libiec61883 libgudev jack2 ];
+
+  mesonFlags = [
+    # Enables all features, so that we know when new dependencies are necessary.
+    "-Dauto_features=enabled"
+    "-Dexamples=disabled" # requires many dependencies and probably not useful for our users
+    "-Dqt5=disabled" # not clear as of writing how to correctly pass in the required qt5 deps
+  ]
+  ++ optional (!gtkSupport) "-Dgtk3=disabled"
+  ++ optionals (!stdenv.isLinux) [
+    "-Djack=disabled" # unclear whether Jack works on Darwin
+  ]
+  ++ optionals (!stdenv.isLinux) [
+    "-Dv4l2-gudev=disabled"
+  ];
 
   # fails 1 tests with "Unexpected critical/warning: g_object_set_is_valid_property: object class 'GstRtpStorage' has no property named ''"
   doCheck = false;