Well, short notice here for everyone coming to this post.
The new Windows build system described on the webpage https://wiki.mudlet.org/w/Compiling_Mud ... on_Windows works great! As it is MSYS based, I'd guess it was made by SlySven. So thank you very much!!!! I just thought I need to post this.
It didn't give me a popup to link with QT though (maybe because it was not my first time installing QTCreator), so I had to find the proper menu to set it myself. But I found my way.
I assume the last post is about compiling the tests. I might need to come back to this on a while, because I've have some ideas/plans regarding the LinkStore (which is used in one of the tests), but there are two other things I need to finish first. So it might need quite some time.