drirc: Add "Unigine Oil Rush" quirk (allow_glsl_extension_directive_midshader).
Appears to fix shader compilation. Tested by starting the client and observing
that the screen was correct after the trailers ran when previously, it was
blank. Play tested on amd64.
This was suggested by "Kuuchan" on the Steam forums:
https://steamcommunity.com/app/200390/discussions/0/
540731690861139279/?insideModal=1#
c594820656479479870
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>