devel: OE recipes missing pkgconfig inherit

Right these days on the OE mailing lists are flowing a number of big changes for master (next release after hardknott, honister).

Amongst these the one in topic: it appears that many recipes were missing that inherit.

See for oe-core

https://lists.openembedded.org/g/openembedded-core/message/156175

and meta-openembedded

https://lists.openembedded.org/g/openembedded-devel/message/93050

I am pretty sure we should double check the recipes in meta-openpli as well.

Cheers

A.A.