configure fails to detect missing SSL_CTX_set_tlsext_ticket_key_cb

The problem is that we only try to compile this, presumably not link it? Hence, without an explicit -Werror to configure, platforms which do not support the session ticket extension (e..g. RHEL5) can not compile.

The problem stems from the fact that without -Werror, the compiler simply says:

conftest.c:56: warning: implicit declaration of function 'SSL_CTX_set_tlsext_ticket_key_cb'