For some types of targets, we pretty much know what kinds of files all
the dependencies are.  For some, however, we can't assume anything,
and are faced with dependencies in platform agnostic form.  We need to
find those in diverse places in %unified_info, and deduce from there
how they should be converted to a platform specific form.
Reviewed-by: NTomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15436)