How to buildlink headers from share/<package>/include

[Mayuresh <mayuresh%acm.org@localhost>]

I am trying to build wip/ghdl-yosys-plugin (not committed).

It depends on devel/yosys headers, which in pkgsrc have a slightly
different path: $prefix/share/yosys/include

devel/sysos does not provide a buildlink.

If I run package's `make' manually in ${WRKSRC} it runs fine, though when
run through pkgsrc it does not find the yosys headers. May be the headers
are needed in .buildlink? And in this scenario how to create the required
links?

-- 
Mayuresh