image_types_wic.bbclass has a mechanism for doing variable substitution
on .wks files by simply letting the input file be called
.wks.in. However, that doesn't allow using variables in files included
via the include directive. This is unfortunate, because lacking either
the ability to include other files or variable substitution leads to
fragile and error-prone duplication between kickstarter files and
recipes/configuration files used for various boards.
This adds (somewhat naive) support for variable substitution in all
files parsed by wic. The user should add all required variables to
WICVARS to get them exported appropriately.
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
