[OE-core] how to get OE/rpm5 and rpms being built with rpm4 on centos7 to play together?

[Robert P. J. Day]

   was just presented with the following issue ... friend was asked to start
creating RPMs to add to a system being created with wind river linux 7 (soon
to be WRL8), but effectively, yocto project. last time i looked, YP uses
rpm5 and i never thought too much about it.

   said friend, however, has a home-grown build system that involves
hand-rolled spec files and running "rpmbuild" manually on centos 7,
which uses rpm4, which means (as i gather) that the generated rpms
are simply incompatible with the target system. so, possible solutions?

   one is to recreate the target system entirely with a PREFERRED_VERSION
for rpm of 4, but that seems like overkill.

   second is to somehow get rpmbuildv5 onto his centos 7 box, and alter
his search path to pick up that version just for the sake of his build.

   last option (and my preference) is to ditch his whole hand-rolling
and use YP (in this case, WRL) and define actual recipes for his
software and build that way.

   thoughts? am i understanding the problem here correctly? is there a
simpler solution i'm overlooking? thanks.

rday