Commands written in Go depend on Go packages, so they
cannot be built by src/cmd/make.bash.  They have been
built by src/make.bash after all the packages are done, but
we want to be able to use cgo (written in Go) during the build
of package net.  To make this possible, build the commands
from src/pkg/Makefile instead of src/make.bash, so that they
are included in the package dependency analysis.

R=r
CC=golang-dev
https://golang.org/cl/1972046