38.13.2. QEMU build variants
Analogous to the Linux kernel build variants but with the --qemu-build-id option instead:
./build-qemu git -C "$(./getvar qemu_source_dir)" checkout v2.12.0 ./build-qemu --qemu-build-id v2.12.0 git -C "$(./getvar qemu_source_dir)" checkout - ./run ./run --qemu-build-id v2.12.0