We should process `build-options`
Those should translate to something similar to:
variables:
(?):
- target_arch == "i386" or target_arch == "x86_64":
gallium_drivers: "svga,swrast,nouveau,r600,r300,radeonsi"
dri_drivers: "swrast,nouveau,radeon,r200,i915,i965"
vulkan_drivers: "intel"
- target_arch == "arm" or target_arch == "aarch64":
gallium_drivers: "swrast,nouveau,freedreno,vc4"
dri_drivers: "swrast,nouveau,radeon,r200"
Then those variables should be used in the configure-commands:
--with-gallium-drivers=%{gallium_drivers} \
--with-dri-drivers=%{dri_drivers} \
--with-vulkan-drivers=%{vulkan_drivers}