Currently it fails as:
go tool dist: $GOROOT is not set correctly or not exported
GOROOT=c:\go
c:\go\include\u.h does not exist
Fail.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/42550044
Fixes#5537.
To avoid `go install -v race std` replacing cmd/cgo with a race enabled version and another package trying to build a cgo enabled package, always build cmd/cgo race enabled before doing the rest of the build.
R=remyoudompheng, rsc, dvyukov, minux.ma
CC=golang-dev
https://golang.org/cl/14071044