Revert Merge x-updates into master due to mesa bloat

See #490 discussion.

This reverts commit 1278859d31, reversing
changes made to 0c020c98f9.

Conflicts:
	pkgs/desktops/xfce/core/xfce4-session.nix (take master)
	pkgs/lib/misc.nix (auto)

pkgs/development/libraries/glib/2.34.x.nix

@@ -1,5 +1,5 @@
-{ stdenv, fetchurl, pkgconfig, gettext, perl, libiconvOrEmpty, zlib, libffi
-, python, pcre, libelf }:
+{ stdenv, fetchurl, pkgconfig, gettext, perl, libiconvOrNull, zlib, libffi
+, python, pcre }:
 
 # TODO:
 # * Add gio-module-fam
@@ -11,29 +11,16 @@
 #     Reminder: add 'sed -e 's@python2\.[0-9]@python@' -i
 #       $out/bin/gtester-report' to postInstall if this is solved
 
-let
-  # some packages don't get "Cflags" from pkgconfig correctly
-  # and then fail to build when directly including like <glib/...>
-  flattenInclude = ''
-    for dir in $out/include/*; do
-      cp -r $dir/* "$out/include/"
-      rm -r "$dir"
-      ln -s . "$dir"
-    done
-    ln -sr -t "$out/include/" $out/lib/*/include/* 2>/dev/null || true
-  '';
-in
-
 stdenv.mkDerivation (rec {
-  name = "glib-2.36.1";
+  name = "glib-2.34.0";
 
   src = fetchurl {
-    url = "mirror://gnome/sources/glib/2.36/${name}.tar.xz";
-    sha256 = "090bw5par3dfy5m6dhq393pmy92zpw3d7rgbzqjc14jfg637bqvx";
+    url = "mirror://gnome/sources/glib/2.34/${name}.tar.xz";
+    sha256 = "f69b112f8848be35139d9099b62bc81649241f78f6a775516f0d4c9b47f65144";
   };
 
   # configure script looks for d-bus but it is only needed for tests
-  buildInputs = [ libelf ] ++ libiconvOrEmpty;
+  buildInputs = [ libiconvOrNull ];
 
   nativeBuildInputs = [ perl pkgconfig gettext python ];
 
@@ -41,16 +28,11 @@ stdenv.mkDerivation (rec {
 
   configureFlags = "--with-pcre=system --disable-fam";
 
-  postConfigure = "sed '/SANE_MALLOC_PROTOS/s,^,//,' -i config.h"; # https://bugzilla.gnome.org/show_bug.cgi?id=698716 :-)
-
   enableParallelBuilding = true;
 
-  postInstall = ''rm -rvf $out/share/gtk-doc'';
+  passthru.gioModuleDir = "lib/gio/modules";
 
-  passthru = {
-     gioModuleDir = "lib/gio/modules";
-     inherit flattenInclude;
-  };
+  postInstall = ''rm -rvf $out/share/gtk-doc'';
 
   meta = {
     description = "GLib, a C library of programming buildings blocks";