fix merge botches.

re-add files autoconf files that the build sort of needs at
least configure for. command used:

% cd /usr/xsrc/external/mit/xf86-video-intel/dist
% autoreconf -I m4 -I /usr/xsrc/external/mit/xorg-server/dist -i

tested on sandy bridge and kaby lake.

merge xf86-video-intel 6afed33b2d673d88674f0c76efe500ae414e8e1b.

initial import of xf86-video-intel-2.99.917

Import the latest from x.org; no improvement over the current screen corruption.

initial import of xf86-video-intel-2.21.15