from -V key it looks like current curl in Yakkety is built with GnuTLS
silpol@lorry:~$ curl -V curl 7.50.1 (x86_64-pc-linux-gnu) libcurl/7.50.1 GnuTLS/3.5.3 zlib/1.2.8 libidn/1.33 librtmp/2.3 Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL libz TLS-SRP UnixSockets
from -V key it looks like current curl in Yakkety is built with GnuTLS
silpol@lorry:~$ curl -V pc-linux- gnu) libcurl/7.50.1 GnuTLS/3.5.3 zlib/1.2.8 libidn/1.33 librtmp/2.3
curl 7.50.1 (x86_64-
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp
Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL libz TLS-SRP UnixSockets