Allow "devtool add" to support adding an out-of-tree kernel recipe given a source tree. I looked into this a bit, and whilst we do have a class and a hello-mod example in meta-skeleton, unfortunately most of the out-of-tree modules I tried to build with it didn't work out of the box since their makefiles didn't understand "modules_install"; apparently we can't rely on much uniformity in terms of how these might be built. Still, we might be able to examine the makefile and make some guesses.
Implemented in master: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=b145480d44b391ce9467389b4f1fbcd40fe4e269 http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=5cf15ffecc4c1602190207870b8edf08d7bf8001