Don't copy from %target to %config so much, see %config as a complement

We copied $target{cflags}, $target{defines} and a few more to %config,
just to add to the entries.  Avoid doing so, and let the build templates
deal with combining the two.

There are a few cases where we still fiddle with %target, but that's
acceptable.

Reviewed-by: Andy Polyakov <appro@openssl.org>