Prototype for X509_check_host() has changed, detect this in configure.ac ChangeLog addition: 2015-04-09 Aidan Kehoe <kehoea@parhasard.net> * configure.ac: If X509_check_host() is available, check the number of arguments it takes. Don't use it if it takes any number of arguments other than five. Also don't use it if <openssl/x509v3.h> does not declare it, since if that is so there is no portable way to tell how many arguments it should take, and so we would end up smashing the stack. * configure: Regenerate. src/ChangeLog addition: 2015-04-09 Aidan Kehoe <kehoea@parhasard.net> * tls.c: #include <openssl/x509v3.h> for its prototype for X509_check_host(). * tls.c (tls_open): Pass the new fifth argument to X509_check_host().