Build files: Make it possible to source libraries into other libraries

Build files: Make it possible to source libraries into other libraries

Added functionality to use static libraries as source for other
libraries.  When done this way, the target library will use the object
files from the sourced static libraries, making the sourced libraries
work as "containers" for object files.

We also need to make sure that the Unix Makefile template knows how to
deal with shared libraries and modules that depend on static libraries.
That's new situation we haven't had before.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10088)