Request: Add GH Action to build the library (with manual trigger from PR)

[diggit]

It would be very much convenient if it was possible to trigger GH Action to build the scopehal library to validate any (PR) changes. It does not have to run on every push, just manual trigger would be enough.

In #1017 , I've got report about error when building on windows. My development environment is on linux and this would help me to spot it sooner.

I think most of the configuration could be taken from https://github.com/ngscopeclient/scopehal-apps

[azonenberg]

This would be nice, but nobody's had the time to work on it. Feel free to send a PR.

One of the challenges is going to be keeping this and the scopehal-apps build environments in sync (is there some way to do it automatically, perhaps by pulling scopehal-apps then force-updating the scopehal pointer to the CI version?)

Also, duplicate of #668 so please use that ticket for any further discussion.