My guess is that this is likely for FreeBSD 12. As xtaz and SirDice have said, ftp/curl's and other ports' full or default features are incompatible with it.What's the correct procedure to completely replace OpenSSL with LibreSSL in FreeBSD 11.1-RELEASE?
DEFAULT_VERSIONS+=ssl=libressl
OPTIONS_UNSET= GSSAPI_BASE
OPTIONS_SET= GSSAPI_HEIMDAL # or GSSAPI_MIT
# or for specificity, since few ports default to GSSAPI_BASE and OpenSSL
ftp_curl_UNSET= GSSAPI_BASE
ftp_curl_SET= GSSAPI_HEIMDAL # or GSSAPI_MIT
# Is the following a such option?
ftp_curl_DEFAULT_VERSIONS+=ssl=openssl # ????