Migrate Windows build to a Linux VM
@inso mentionned that it is possible to make Windows build inside Linux, giving this example: https://github.com/spesmilo/electrum/blob/master/contrib/build-wine/build-electrum-git.sh#L68
The trick is to use Wine.
This could be helpful to avoid the superhigh load involved by a Windows VM, and have only one Vagrant VM to make the build, or even a docker container.