Move at_spi2_core and at_spi2_atk outside of the gnome3 attrset

pkgs/development/libraries/at-spi2-core/default.nix

@@ -0,0 +1,32 @@
+{ stdenv, fetchurl, python, pkgconfig, popt, intltool, dbus_glib
+, libX11, xextproto, libSM, libICE, libXtst, libXi, gobjectIntrospection }:
+
+stdenv.mkDerivation (rec {
+  versionMajor = "2.12";
+  versionMinor = "0";
+  moduleName   = "at-spi2-core";
+  name = "${moduleName}-${versionMajor}.${versionMinor}";
+
+  src = fetchurl {
+    url = "mirror://gnome/sources/${moduleName}/${versionMajor}/${name}.tar.xz";
+    sha256 = "12gvsgdaxnxskndlhlmdkc50cfqgmzfc4n8la9944fz5k3fhwmfv";
+  };
+
+  buildInputs = [
+    python pkgconfig popt  intltool dbus_glib
+    libX11 xextproto libSM libICE libXtst libXi
+    gobjectIntrospection
+  ];
+
+  # ToDo: on non-NixOS we create a symlink from there?
+  configureFlags = "--with-dbus-daemondir=/run/current-system/sw/bin/";
+
+  meta = with stdenv.lib; {
+    platforms = platforms.linux;
+  };
+}
+  // stdenv.lib.optionalAttrs stdenv.isDarwin {
+    NIX_LDFLAGS = "-lintl";
+  }
+)
+