Make unneeded packages for read-only rootfs configurable

We use a read-only rootfs (i.e., we have read-only-rootfs set in IMAGE_FEATURES). However, we mount /etc from a separate writable flash partition. But because of how some packages are considered unneeded and subsequently removed from the rootfs if it is read-only, we cannot enable, e.g., shadow in our image. The list of unneeded packages is hardcoded in lib/oe/rootfs.py, making it near impossible to override this.

With this change the list of unneeded packages is moved to a variable (ROOTFS_RO_UNNEEDED) in image.bbclass, which makes it easy to adopt it as needed.

There was code in lib/oe/rootfs.py which was meant to not add update-rc.d to the list of unneeded packages if both systemd and sysvinit are enabled in DISTRO_FEATURES. I have removed this code since a) it is no longer needed (as it only made sense when the unneeded packages were removed based on whether package-management was enabled or not), and b) it can never have worked as intended (because the explicit addition of update-rc.d to the list of unneeded packages was not removed when the conditional addition was introduced...)

//Peter

The following changes since commit 53b5dc0dda3fa7703e8f6a68b05b565ecee9e41f:

gcc: Fix musl ldso name for mips64 (2016-03-30 21:24:02 +0100)

are available in the git repository at:

git://git.yoctoproject.org/poky-contrib pkj/unneeded_packages
http://git.yoctoproject.org/cgit.cgi/poky-contrib/log/?h=pkj/unneeded_packages

Peter Kjellerstedt (1):
image.bbclass: Make unneeded packages for a read-only rootfs
configurable

 meta/classes/image.bbclass |  6 +++++-
 meta/lib/oe/rootfs.py      | 23 +++++------------------
 2 files changed, 10 insertions(+), 19 deletions(-)

2.1.0