This connects up the configuration message, and uses it to allow the client to set the environment
in the config passed to packages.Load
Change-Id: I75e03c01c74e9b11c8b4c47b9cbdd0574cddf778
Reviewed-on: https://go-review.googlesource.com/c/tools/+/169704
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>