Implementing additional SPECS in genode-world

[Johannes Schlatow]

> Hi Johannes,
> 
> > The point where I got stuck, however, is that I need to include the
> > less-specific configuration files within base-hw, which I achieve
> > by the following line:
> > 
> > 	include $(call
> > select_from_repositories,lib/mk/spec/zynq/core.inc)
> > 
> > Now, the issue is that including makefiles from other repositories
> > won't work properly. This is due to the fact that $REP_DIR (used
> > e.g. in core.inc) will evaluate to `[...]/repos/world` and not
> > `[...]/repos/base-hw`.
> > 
> > Do you have any idea on how to work around this or even on how to
> > improve the build system in order to support this use case?  
> 
> Hosting core.mk files outside the base-hw repository is a new pattern
> for us, but I see the appeal.
> 
> REP_DIR always points to the repository where the target resides - in
> your case, this is the core.mk library. The simplest solution would be
> to replace the occurrences of REP_DIR in core.inc by a new variable
> BASE_HW_DIR, which has to be defined by the one to includes core.inc.
> The core.mk files within the base-hw repository would simply define to
> as $(REP_DIR) but your "foreign" core.mk file could set the variable
> explicitly to the location of the base-hw repository.
> 
> Would that solve your problem?

Yes, that would solve the problem. Thank you.