Hi, see https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=208584 As the maintainer of squid has no solution I raise a ticket here. Trying to update squid to 3.5.17_1 brought up the issue again and uninstalling libressl, upgrading ports and then installing again (required e.g. openntpd) is not really user friendly.
With libressl installed: configure: OpenSSL library support: yes -L/usr/local/lib -L/usr/local/lib -lssl -lcrypto Without libressl installed: configure: OpenSSL library support: yes -L/usr/lib -lssl -lcrypto
*** This bug has been marked as a duplicate of bug 208584 ***