feat(build_library): put all of the partition stuff behind a flag
feat(build_library): put all of the partition stuff behind a flag

this lays the groundwork for supporting a cpio img which doesn't have
partitions.

sigma/coreos-scripts,bcwaldon/coreos-scripts,marineam/coreos-scripts,gtank/scripts,vmware/coreos-scripts,nicescale/scripts,mischief/scripts,glevand/coreos--scripts,fivethreeo/scripts,andrejro/coreos--scripts,marineam/coreos-scripts,BugRoger/scripts,gtank/scripts,trnubo/scripts,coreos/scripts,BugRoger/scripts,mjg59/scripts,zhang0137/scripts,fivethreeo/scripts,trnubo/scripts,endocode/scripts,zhang0137/scripts,vmware/coreos-scripts,endocode/scripts,smilart/scripts,nicescale/scripts,mjg59/scripts,smilart/scripts,sigma/coreos-scripts,vmware/coreos-scripts,crawford/scripts,andrejro/coreos--scripts,glevand/coreos--scripts,sigma/coreos-scripts,fivethreeo/scripts,bcwaldon/coreos-scripts,smilart/scripts,gtank/scripts,mjg59/scripts,nicescale/scripts,bcwaldon/coreos-scripts,crawford/scripts,mischief/scripts,andrejro/coreos--scripts,zhang0137/scripts,coreos/scripts,BugRoger/scripts,marineam/coreos-scripts,trnubo/scripts,endocode/scripts,crawford/scripts,mischief/scripts