For various reasons, like debugging or compliance, it is important to
identify what br2-external trees versions were used for a specific
build.
Add a Kconfig option that contains the version as computed by
support/scripts/setlocalversion; this will appear in the .config file
(but not in defconfig files, which is what we want).
Also generate that variable on the .mk side, so that it gets properly
exported in the environment, for post-build of post-iamge scripts to use
as they see fit (like, ensuring there is no dirtyness when in a CI for
example).
Reported-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
9ae089e2e9