[OE-core] [PATCH resend] wic: allow bitbake variables in kickstarter files

[Rasmus Villemoes]

On 2018-07-03 14:54, Rasmus Villemoes wrote:
> 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.

ping^n