openssl: enable parallel build and installation

This is a patch that is originally based on a patch Thomas P.
submitted for an earlier version of this package. I have adopted this
patch to use the latest available Gentoo parallel patch. I have also
seen about a minute improvement on my build times of openssl.

Part of Thomas P's original message:

On my build server, the current build of OpenSSL takes 1 minutes and
20 seconds. With this commit applied, enabling parallel build and
installation, the build only takes 28 seconds.

All the patches are downloaded from Gentoo.

There is apparently some interest in upstream OpenSSL to enable
parallel build, see for example commit
https://github.com/openssl/openssl/commit/c3f22253b139793ff3b91ff7e6969e180cf06815

. This
commit is not part of any OpenSSL release, but we can hope that the
problem will resolved in the future.

Signed-off-by: Ryan Barnett <ryanbarnett3@gmail.com>
CC: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
CC: Gustavo Zacarias <gustavo@zacarias.com.ar>
CC: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>