Using LibreSSL with only one or a subset of all installed ports

[Nick Rogers]

I am wondering if it is wise or possible to use libressl for only a single
installed port, while continuing to use OpenSSL from Base for all remaining
installed ports. I would like to do this in order to get around the fact
that lang/phantomjs does not compile against openssl 1.1.x due to API
changes, and fixing it is less than trivial. However, I am not quite ready
to switch other ports to LibreSSL.

My thought was to use the following approach in make.conf when building via
poudriere.

.if ${.CURDIR:M*/lang/phantomjs}
DEFAULT_VERSIONS+= ssl=libressl
.endif

I am hoping for some advice as to whether or not this will work, or if its
a terrible idea, or if there is perhaps a better way to toggle libressl
per-port. All the port documentation I can find suggests an outright switch
to libressl for all ports, so I am concerned there is something I am
missing that will not be happy?

Thank you!

-Nick