Update cppcheck version to 2.16.0

[matt335672]

Bumps the cppcheck version from 2.15.0 to 2.16.0

There is also a small change to common/ssl_calls.c.

Initially, this version of cppcheck threw a syntax error on this code:-

#if defined(SSL_CTX_set_ecdh_auto)
    if (!SSL_CTX_set_ecdh_auto(self->ctx, 1))
    {
        LOG(LOG_LEVEL_WARNING, "TLS ecdh auto failed to be enabled");
    }
#endif

The reason is that cppcheck tries a pass with SSL_CTX_set_ecdh_auto set to 1, which (of course) fails.

The macro was introduced for OpenSSL 1.0.2 (see https://github.com/openssl/openssl/blob/OpenSSL_1_0_2/CHANGES) and disabled for OpenSSL 1.1.0 (see https://github.com/openssl/openssl/blob/OpenSSL_1_1_0/CHANGES). Versions of OpenSSL after 1.1.0 have a compatibility macro which does nothing if the second parameter is non-zero (i.e.):-

#  define SSL_CTX_set_ecdh_auto(dummy, onoff)      ((onoff) != 0)

Solution for the cppcheck issue is to replace the test for the SSL_CTX_set_ecdh_auto macro with explicit version tests.

Another problem with the code was that the macro was being called twice for OpenSSL 3.x. This regression was introduced during the OpenSSL 3.x migration (6cebade). As previously explained there is no need to call this macto for this version of OpenSSL.

@firewave - you asked to be notified for cppcheck-related issues.

[matt335672]

Incidentally, I've tried the latest version of astyle too (3.6.3)

The showstopper we had before is fixed, provided --align-reference-name is added to the config. However there now appears to be a difference with continuation lines within parentheses not being indented, or being indented too much. I've not been able to come up with a way to update astyle yet.