Build rustbook without having to wait 20 min?

I don’t know the magic trick to work on rustbook offhand but rustbook is a pretty simple crate so you can probably build it from the command line. If you run make VERBOSE=1 you can see the commands being executed and then copy them for your own use.

In some places the build system supports setting NO_REBUILD=1 to short-circuit the bootstrap, but it almost certainly doesn’t work for rustbook.