Error when compiling with fonts

So I did a test with Sage 9.x release and Sage 9.x update branch and noticed that albeit there is a fonts/ folder in assets/ (using a .gitkeep placeholder), there is webpack config in place to copy it over to dist/....
So this has to be added for Sage 9 themes that need fonts/ in dist/...

See this discussion:

One doesn’t have to use the copy plugin - depending on the workflow and conversion/style needs, one can also use something like postcss-font-magician (this was more important in the past, now all browsers support WOFF/WOFF2).