xorg.libXfixes: 5.0.2 -> 5.0.3

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 5.0.3 with grep in /nix/store/g5hcg35wmg25sgfjp7mvi4cx3shldbxd-libXfixes-5.0.3
- directory tree listing: https://gist.github.com/7398ada0908969ebbd1e7e629a1e0ef7

(cherry picked from commit 0e443ceb9e815fda4a580a484ea0b2627ee78509)
Only fixes CVE-2016-7944; /cc #38994.
(cherry picked from commit ce86b8f1b431c635eb1facc5d8b6954dc0ef5b7d)

pkgs/servers/x11/xorg/default.nix

···
   }) // {inherit libX11 xextproto xproto ;};
 
   libXfixes = (mkDerivation "libXfixes" {
-    name = "libXfixes-5.0.2";
+    name = "libXfixes-5.0.3";
     builder = ./builder.sh;
     src = fetchurl {
-      url = mirror://xorg/individual/lib/libXfixes-5.0.2.tar.bz2;
-      sha256 = "1slsk898386xii0r3l7szwwq3s6y2m4dsj0x93ninjh8xkghxllv";
+      url = mirror://xorg/individual/lib/libXfixes-5.0.3.tar.bz2;
+      sha256 = "1miana3y4hwdqdparsccmygqr3ic3hs5jrqfzp70hvi2zwxd676y";
     };
     buildInputs = [pkgconfig fixesproto libX11 xextproto xproto ];
     meta.platforms = stdenv.lib.platforms.unix;