Description:
------------
Testing for LibreSSL and its version number via OPENSSL_VERSION_TEXT is possible but not ideal.

Since 2.2.2 LibreSSL defines LIBRESSL_VERSION_NUMBER. I would prefer to use this.

Please define LIBRESSL_VERSION_NUMBER as a constant in PHP user space, or provide another way to access it.

Test script:
---------------
if (defined('OPENSSL_VERSION_TEXT')) {
    echo 'OPENSSL_VERSION_TEXT is ' . OPENSSL_VERSION_TEXT . "\n";
    if (strpos(OPENSSL_VERSION_TEXT, 'LibreSSL') === 0) {
        echo 'LIBRESSL_VERSION_NUMBER is ' 
            . (defined('LIBRESSL_VERSION_NUMBER') ? dechex(LIBRESSL_VERSION_NUMBER) : 'undefined') 
            . "\n";
    }
} else {
    echo "OpenSSL not presentn\n";
}


Expected result:
----------------
For example...

OPENSSL_VERSION_TEXT is LibreSSL 2.3.1
LIBRESSL_VERSION_NUMBER is 20301000



Actual result:
--------------
For example...

OPENSSL_VERSION_TEXT is LibreSSL 2.3.1
LIBRESSL_VERSION_NUMBER is undefined