commit 3bb46f5d7d26b272a26c74700c0191346943f3a6
author Todd Wang <toddw@google.com> Thu May 14 22:01:18 2015 -0700
committer Todd Wang <toddw@google.com> Thu May 14 22:01:18 2015 -0700
tree a4843a74c4748073a0fee14256c20ee8cbb88a21
parent 8123b5eda8b2ff6bd9d070f2e24c70dc4ad1a33a

ref: Replace x/devtools/internal/envutil with x/lib/envvar

A while ago I wrote envutil in the devtools repo, to make it
easier to deal with environment variables, and to make it easy
for the v23 tool to keep track of the mutations it had made.

Later on I noticed that there was similar code in x/ref in a few
places.

This CL removes envutil, and adds a new package envvar that may
be used by all other packages.  It behaves similarly to envutil,
and also to the code scattered around x/ref.

In a subsequent CL I'll add cmdline support for environment
variables using envvar.

MultiPart: 2/2

Change-Id: Idd5c06ab79badf678cd5ce7e87493c04ea16204a