Yes, it is possible. The Go GC is written in the Go subset that can be compiled without heap allocation. The compiler even has a switch for this, which turns any heap allocation into a compile error. This is a subset of all possible Go programs, but still a very useful one.
Sorry, I don't know and haven't been able to locate it in the help for the build tool, but it was mentioned in a talk about the GC, especially about it being written in Go itself.
