super-ub-kernel-scan-wip:  find all kernels on system & detect type
super-ub-kernel-scan-wip:  find all kernels on system & detect type

This branch is to work out scanning all kernels on the system.

** Kernel directory selection **

By default, each directory in KSOURCE_LOCATION_HINTS is checked for
kernels.  Additional directories may be added using
--with-extra-kernel-sources="<dir> <dir>..."

Obvious problem entries (dupes, non-existent) are culled.

** Kernel directory testing **

Each directory is tested to contain a configured kernel source.  That
simply means .config and include/linux/version.h exist.

If shmdrv is enabled, add this directory to the shmdrv kernel list.

Next, unless xenomai kernels were specified using
--with-xenomai-kernel-sources, check if this is a xenomai kernel by
grepping for CONFIG_XENOMAI in .config, and add to the xenomai kernel
list if found.

Finally, do the same thing for RTAI, testing by grepping for
rt_daemonize in Module.symvers.

** --with-foo-kernel-sources **

If these flags (foo is one of xenomai, rtai, shmdrv) present on the
configure command line, only consider those directories for that type
of kernel.

ArcEye/machinekit-testing,ArcEye/MK-Qt5,EqAfrica/machinekit,ArcEye/machinekit-testing,unseenlaser/machinekit,cdsteinkuehler/linuxcnc,unseenlaser/machinekit,cdsteinkuehler/linuxcnc,unseenlaser/machinekit,unseenlaser/machinekit,strahlex/machinekit,kinsamanka/machinekit,kinsamanka/machinekit,araisrobo/machinekit,ArcEye/MK-Qt5,cdsteinkuehler/MachineKit,strahlex/machinekit,bobvanderlinden/machinekit,araisrobo/machinekit,cdsteinkuehler/MachineKit,EqAfrica/machinekit,bobvanderlinden/machinekit,ArcEye/MK-Qt5,ArcEye/machinekit-testing,unseenlaser/machinekit,strahlex/machinekit,ArcEye/machinekit-testing,RunningLight/machinekit,araisrobo/machinekit,RunningLight/machinekit,araisrobo/machinekit,mhaberler/machinekit,Cid427/machinekit,cdsteinkuehler/linuxcnc,EqAfrica/machinekit,Cid427/machinekit,ArcEye/MK-Qt5,cdsteinkuehler/linuxcnc,RunningLight/machinekit,cdsteinkuehler/MachineKit,strahlex/machinekit,Cid427/machinekit,bobvanderlinden/machinekit,unseenlaser/machinekit,cdsteinkuehler/MachineKit,mhaberler/machinekit,EqAfrica/machinekit,kinsamanka/machinekit,mhaberler/machinekit,Cid427/machinekit,ArcEye/machinekit-testing,strahlex/machinekit,ArcEye/MK-Qt5,Cid427/machinekit,mhaberler/machinekit,unseenlaser/machinekit,EqAfrica/machinekit,cdsteinkuehler/linuxcnc,EqAfrica/machinekit,RunningLight/machinekit,ArcEye/machinekit-testing,araisrobo/machinekit,Cid427/machinekit,kinsamanka/machinekit,ArcEye/machinekit-testing,unseenlaser/machinekit,Cid427/machinekit,kinsamanka/machinekit,mhaberler/machinekit,araisrobo/machinekit,bobvanderlinden/machinekit,cdsteinkuehler/MachineKit,ArcEye/MK-Qt5,mhaberler/machinekit,cdsteinkuehler/MachineKit,bobvanderlinden/machinekit,araisrobo/machinekit,strahlex/machinekit,araisrobo/machinekit,bobvanderlinden/machinekit,kinsamanka/machinekit,RunningLight/machinekit,EqAfrica/machinekit,ArcEye/MK-Qt5,cdsteinkuehler/linuxcnc,bobvanderlinden/machinekit,mhaberler/machinekit,ArcEye/MK-Qt5,ArcEye/machinekit-testing,bobvanderlinden/machinekit,mhaberler/machinekit,kinsamanka/machinekit,araisrobo/machinekit,RunningLight/machinekit,RunningLight/machinekit,EqAfrica/machinekit,kinsamanka/machinekit,RunningLight/machinekit,strahlex/machinekit,Cid427/machinekit