which bits to build, and to allow "make -j N" actually do something in
parallel:
- build_kernels: for each of ${ALL_KERNELS}, create kern-${NAME} target
which configures & builds the kernel ${NAME}.
- build_kernsets: for each of ${KERNEL_SETS}, create kernset-${NAME} target
to create ${RELEASEDIR}/binary/sets/kern-${NAME}.tgz
- build_releasekernels: for each of ${KERNEL_SETS} ${EXTRA_KERNELS}, create
${RELEASEDIR}/binary/kernel/netbsd-${NAME}.gz (et al)
(The latter two .WAIT until build_kernels has completed)