Looks like you already figured out that you need to rebuild the Joker executable via go build -tags go_spew (thanks for submitting the Issue re the “go builds” typo!), in which case:

$ go build -tags go_spew
$ ./joker
Welcome to joker v0.15.3. Use '(exit)', EOF (Ctrl-D) or SIGINT (Ctrl-C) to exit.
user=> (joker.core/go-spew :hey {:MaxDepth 5 :Indent "  " :UseOrdinals true})
(core.Keyword) {
  InfoHolder: (core.InfoHolder) {
    info: (*core.ObjectInfo)(#1)({
      Position: (core.Position) {
        endLine: (int) 1,
        endColumn: (int) 24,
        startLine: (int) 1,
        startColumn: (int) 21,
        filename: (*string)(#2)((len=6) "<repl>")
      }
    })
  },
  ns: (*string)(<nil>),
  name: (*string)(#3)((len=3) "hey"),
  hash: (uint32) 819820356
}
true
user=>