security/php70-openssl and security/php71-openssl: fix build with libressl-devel

LibreSSL 2.7 brings out a number of incompatibilities.
The new patch allows PHP to compile against the new LibreSSL version.

It is ported from security/php72-openssl in r468343

PR: 226902
Submitted by: Piotr Kubaj <pkubaj@anongoth.pl>