Running gomobile init downloads the appropriate Android NDK compiler toolchain and builds a Go cross compiler. Details: https://docs.google.com/document/d/1cePOQ35PNEb_QqxnPAmBv0cEnAm7AQSGuz9wVeJ-lBs/edit?usp=sharing Change-Id: I279f6ff0753f8776ae7d98f33a85ee4d0bbf5390 Reviewed-on: https://go-review.googlesource.com/3971 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>