Implement IMAGE_FEATURES in a general way

From: Chris Larson <[email protected]>

This is a second attempt at this, scrapping the class changes from the previous request and redoing it in a less invasive way, and breaking up the changes into 3 pieces. This implements IMAGE_FEATURES. IMAGE_FEATURES is analagous to DISTRO_FEATURES and MACHINE_FEATURES, for root filesystem construction. Currently, the only supported features are any defined package groups, as used by the oe.packagegroup python module.

Example usage:

PACKAGE_GROUP_myfeature = "vim iptables"
IMAGE_FEATURES += "myfeature"

This also makes the dev-pkgs and dbg-pkgs features general, and adds a doc-pkgs feature.

The following changes since commit 866a34dd80228a0c10cbea5d7715e2acd6cea131:

uclibc_0.9.32: Sync mount.h from eglibc (2011-08-09 15:17:45 +0100)

are available in the git repository at:
git://github.com/kergoth/oe-core feature/image_features

go here for github's branch comparison interface:
https://github.com/kergoth/oe-core/compare/master...feature%2Fimage_features

Chris Larson (3):
image: implement IMAGE_FEATURES
image: add support for generally useful {dev,doc,dbg}-pkgs features
core-image: adjust to use the new IMAGE_FEATURES support

 meta/classes/core-image.bbclass |   77 +++++++++------------------------------
 meta/classes/image.bbclass      |   47 ++++++++++++++++++++++--
 2 files changed, 61 insertions(+), 63 deletions(-)

1.7.4.1