chocolate-doom: add patch to fix static linking

chocolate-doom: add patch to fix static linking

This commit adds a backported upstream patch which modifies the
configure script so that it uses pkg-config to detect libraries and
their static linking dependencies.

It also adds host-pkgconf as a dependency and removes the SDL static
linking workaround from chocolate-doom.mk as it's no longer necessary.

Fixes:

  http://autobuild.buildroot.net/results/d98/d981499ad82121d58fb7584b55d09c484cb6aa49/
  http://autobuild.buildroot.net/results/e41/e419f29e14edd28cbf48278bef725b696ae8ef70/
  http://autobuild.buildroot.net/results/d8f/d8fe9b5bdb262e939d4150804ea34777c91d3c04/
  ...

Signed-off-by: Rodrigo Rebello <rprebello@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>