Update API for OpenSSL 1.1.1d, and speed up on patterns like "^foo"

[reach4nk]

This merges the changes suggested by @jroeger23 under 37 and @starius under 25.

I have OpenSSL 1.1.1d installed an ran into trouble while compiling it on OpenSSL devs changed their API (https://wiki.openssl.org/index.php/1.1_API_Changes

This is my setup, on which it has been tested:

Linux 5.4.51+ #1333 Mon Aug 10 16:38:02 BST 2020 armv6l GNU/Linux
gcc 8.3.0
OpenSSL 1.1.1d  10 Sep 2019