Although the gnuplot code itself compiles successfully using visual c, all the cairo terminals as well as png, jpeg, etc. using gdlib cannot be done without a lot of previous experience. This is mostly because those libraries, too, have very little/outdated build instructions for vc.
Also there is no information available on the packaging for the windows installer that has been used in the past, so that someone could volunteer to make an installer for gp4.6.4 without re-inventing the whole thing.
And the build instructions don´t say anything about the recommended (or last known-to-work) versions of all the libraries, so that one could first try those before attempting to update them. For example gdlib has a new version 2.1.0, while the recommended binary of the earlier version has vanished from the web.
I fear if this keeps up, gnuplot might loose the ability to work under windows at all.