clover: Fix build after clang r348827

CodeGenOptions were moved to Basic.

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Aaron Watry <awatry@gmail.com>
Tested-by: Aaron Watry <awatry@gmail.com>
Reviewed-by: Kai Wasserbäch <kai@dev.carbon-project.org>
CC: mesa-stable@lists.freedesktop.org
(cherry picked from commit e4f9a37a)