packaging: optionally use "make -j" for the deb
packaging: optionally use "make -j" for the deb

The debian build system examines the environment variable DEB_BUILD_OPTIONS,
which consists of a comma-separated list of build options.  If it includes
"parallel=X", the "make" and "make docs" steps of the package build will be
done with "make -j X".

kinsamanka/machinekit,bmwiedemann/linuxcnc-mirror,RunningLight/machinekit,araisrobo/linuxcnc,aschiffler/linuxcnc,ArcEye/machinekit-testing,ianmcmahon/linuxcnc-mirror,RunningLight/machinekit,cdsteinkuehler/MachineKit,mhaberler/machinekit,ikcalB/linuxcnc-mirror,aschiffler/linuxcnc,Cid427/machinekit,ArcEye/MK-Qt5,unseenlaser/machinekit,cnc-club/linuxcnc,cdsteinkuehler/linuxcnc,bobvanderlinden/machinekit,mhaberler/machinekit,EqAfrica/machinekit,cnc-club/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,RunningLight/machinekit,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,cdsteinkuehler/linuxcnc,ArcEye/MK-Qt5,cdsteinkuehler/MachineKit,unseenlaser/machinekit,ArcEye/MK-Qt5,RunningLight/machinekit,unseenlaser/machinekit,cdsteinkuehler/linuxcnc,ArcEye/MK-Qt5,narogon/linuxcnc,cdsteinkuehler/linuxcnc,Cid427/machinekit,EqAfrica/machinekit,araisrobo/linuxcnc,ianmcmahon/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,araisrobo/machinekit,bmwiedemann/linuxcnc-mirror,bobvanderlinden/machinekit,ianmcmahon/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,kinsamanka/machinekit,ArcEye/machinekit-testing,EqAfrica/machinekit,strahlex/machinekit,narogon/linuxcnc,EqAfrica/machinekit,EqAfrica/machinekit,araisrobo/machinekit,ArcEye/machinekit-testing,narogon/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,cdsteinkuehler/MachineKit,araisrobo/linuxcnc,ikcalB/linuxcnc-mirror,jaguarcat79/ILC-with-LinuxCNC,strahlex/machinekit,cnc-club/linuxcnc,RunningLight/machinekit,jaguarcat79/ILC-with-LinuxCNC,unseenlaser/linuxcnc,cdsteinkuehler/MachineKit,Cid427/machinekit,unseenlaser/machinekit,Cid427/machinekit,araisrobo/machinekit,strahlex/machinekit,aschiffler/linuxcnc,mhaberler/machinekit,mhaberler/machinekit,bobvanderlinden/machinekit,ArcEye/machinekit-testing,kinsamanka/machinekit,ArcEye/MK-Qt5,ikcalB/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,bmwiedemann/linuxcnc-mirror,araisrobo/machinekit,unseenlaser/linuxcnc,unseenlaser/linuxcnc,RunningLight/machinekit,bobvanderlinden/machinekit,mhaberler/machinekit,ArcEye/MK-Qt5,ianmcmahon/linuxcnc-mirror,aschiffler/linuxcnc,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,EqAfrica/machinekit,unseenlaser/linuxcnc,narogon/linuxcnc,unseenlaser/machinekit,RunningLight/machinekit,ArcEye/MK-Qt5,mhaberler/machinekit,cnc-club/linuxcnc,RunningLight/machinekit,strahlex/machinekit,araisrobo/linuxcnc,aschiffler/linuxcnc,Cid427/machinekit,araisrobo/machinekit,araisrobo/machinekit,narogon/linuxcnc,strahlex/machinekit,kinsamanka/machinekit,bobvanderlinden/machinekit,strahlex/machinekit,cnc-club/linuxcnc,kinsamanka/machinekit,strahlex/machinekit,unseenlaser/linuxcnc,Cid427/machinekit,EqAfrica/machinekit,araisrobo/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/linuxcnc,EqAfrica/machinekit,unseenlaser/machinekit,cnc-club/linuxcnc,araisrobo/linuxcnc,ArcEye/machinekit-testing,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,kinsamanka/machinekit,unseenlaser/machinekit,ArcEye/MK-Qt5,cdsteinkuehler/linuxcnc,cdsteinkuehler/MachineKit,unseenlaser/machinekit,mhaberler/machinekit,kinsamanka/machinekit,kinsamanka/machinekit,ArcEye/machinekit-testing,cnc-club/linuxcnc,mhaberler/machinekit,Cid427/machinekit,araisrobo/machinekit,jaguarcat79/ILC-with-LinuxCNC,Cid427/machinekit,bobvanderlinden/machinekit,araisrobo/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/MachineKit,bmwiedemann/linuxcnc-mirror,bobvanderlinden/machinekit,bobvanderlinden/machinekit,bmwiedemann/linuxcnc-mirror