SSE is present in bsd.options.desc.mk

SSE_DESC?=              Use SSE optimized routines

why not use '\' to break lines?

Unless you're adding comments to the items, I don't see much points in defining them separately.

In the case of this port, SSE means SSE3, not just any SSE. There are many levels of SSE that various processor families implement.

The generic version of the message would be confusing in this case.

Then maybe make the option SSE3, so that it says what it means.

Why change the framework and not just use something like

.for opt in ${OPTIONS_SINGLE_VECTOR}
${opt}_VARS=    SIMINT_VECTOR=${opt}
.endfor

CMAKE_ARGS=    -DSIMINT_VECTOR:STRING=${SIMINT_VECTOR:S/3//:tl} \

Why change the framework and not just use something like

This is possible. However, OPTIONS_${okind}_${opt}_SELECTED is a very logical and consistently defined feature in itself. It can easily be useful in other contexts to simplify such 3-liners into 1-liners. The implementation in the framework looks quite elegant to me, and is only 9 lines.

I don't know about that.

What I do know is that this review has been open for almost two months now. You probably could commit it now or very soon, if this didn't require the change in D13078 and portmgr@ approval :)

Many reviews have been open for a long time.
There is nothing that says that this is the reason.