fontconfig: stop using xml:space; vital for nixos+2.11

Since fontconfig-2.11 the xml:space attribute makes it reject
/etc/fonts/fonts.conf, so it renders garbage and eats lots of CPU.

To use anything linked to fontconfig-2.11 you need to have this patch
applied to your running NixOS. That's why I'm pushing it to master
before the fontconfig update (as soon as I found and tested the fix).

(cherry picked from commit ec985c8ffa6d29bf50e60ba814e3523ffd4c2919)
nixos/mesa: don't create /run/opengl-driver-32 ...

... if on 64-bit and without 32-bit drivers.

(cherry picked from commit 428469443987e063760cf85235d96f02f51dc891)

Conflicts (still in xserver.nix on release):
	nixos/modules/services/x11/mesa.nix
curl: update 7.33 -> .35, including two security fixes

CVE-2013-4545
CVE-2014-0015

(cherry picked from commit befe6905e2e2de88ab34e7b11608651fc5fd84b1)
gegl: fix CVE-2012-4433 via an Arch patch

(cherry picked from commit c2c50db47d9048c3747850ab25731ba509a0c4a1)