To promote the reuse and sharing of configuration fragments this change
allows any kernel-yocto based recipe to have multiple alternate git repositories
which provide kernel feature directory trees listed on the SRC_URI.
These feature directories are in addition to any in-tree kernel meta data branches
that may be available (described via the KMETA variable in linux-yocto recipes).
Features found within these directories can be used from recipes via the
KERNEL_FEATURES variable. Features found within a feature directory are free
to include any other features that are available in any directories. In both
cases the path to a feature description (a .scc file) is relative to the
root of a given feature directory (which is how existing .scc files work)
The search order for features is determined by the order that repositories
appear on the SRC_URI.
Normal SRC_URI rules apply to any repository that is added as a kernel
feature container. A SRCREV must be supplied and it must be unpacked to
a unique directory, which is controlled via the "destsuffic" url parameter.
In addition to these standard requirements, any kernel feature repository
reference should identify itself via the "type=kmeta" url parameter. If
type=kmeta is not supplied, the repository will not be processed for
kernel features.
As an example, the following in a linux-yocto bbappend makes two additional
feature directories available to KERNEL_FEATURES and fragments.
