I've built the new Guile from source a handful of times now. It's definitely a slow process, but I'm very grateful that Guile doesn't require an older version of itself in order to build like a lot of other self-hosted languages. Self-hosting is good, but it's imperative that users can bootstrap on their own so that they don't have to place trust in a pre-built binary of the compiler in order to build the compiler. For example, Go has a self-hosted compiler now, but you don't need to trust a pre-built Go compiler binary to build Go, because you can bootstrap it using gccgo.