Write set of bitbake variables used by wic into
build/tmp/sysroots/<machine>/imagedata/<image>.env
List of variables is defined in WICVARS variable in
meta/classes/image_types.bbclass.
This is needed for wic to be able to get bitbake variables without
running 'bitbake -e'.
(From OE-Core rev: 861ce6c5d4836df1a783be3b01d2de56117c9863)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>