We need Unixly defaults for config targets that don't inherit a BASE

Ideally, each config target should inherit a base to get their
platform specific defaults.  Unfortunately, that is currently not the
case, so we duplicate the Unixly defaults from the BASE_unix template
into the DEFAULT template.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5177)