Why not just ${MV} ${STAGEDIR}${PREFIX}/examples ${STAGEDIR}${EXAMPLESDIR}?

You do all sorts of example moving stuff in the Makefile. Does this patch wind up doing anything?

Yes, this patch only corrects the path where they are installed.

Makefile then fixes them up so that they can actually be easily run from the same examples directory, because otherwise they can't be run.

pkg-message-examples explains how to run them once the port is installed.

I went an extra-mile and made examples runnable to that it is easier to verify that the library works, and see what other dependencies it needs, because it needs some more libraries optionally.

All this is needed because the upstream again installs it in a very messy way.