I got curious about this so decided to see what exactly is done by fmt.Println. http://golang.org/src/pkg/fmt/print.go
If you scroll to the very bottom, you’ll see an if addnewline where \n is always used. I can’t hardly speak for if this is the most “cross-platform” way of doing it, and go was originally tied to linux in the early days, but that’s where it is for the std lib.
I was originally going to suggest just using fmt.Fprintln and this might still be valid as if the current functionality isn’t appropriate, a bug could be filed and then the code would simply need to be compiled with the latest Go toolchain.