commit f4b236442b963839345b4d66bdb765d7b50b321b
author Todd Wang <toddw@google.com> Mon Feb 29 16:17:24 2016 -0800
committer Todd Wang <toddw@google.com> Mon Feb 29 16:17:24 2016 -0800
tree 0a0b70b0efbe2fb63043ad4064512dd5e75405f0
parent cb23bc703ab5b3f292724d300223067a35b2a580

devtools: Use lookpath package consistently.

Changes the signature of the lookpath functions to:
Look(env map[string]string, ...) (string, error)
LookPrefix(env map[string]string, ...) ([]string, error)

The env map is passed in, rather than a slice of dirs, to
facilitate supporting other platforms in the future.  E.g. on
windows we need to consult both the PATH and PATHDIRS environment
variables.

We now return an error, to more closely match LookPath in
os/exec.  The implementation of these methods has also changed,
to more closely match the os/exec implementation.

Also removed the copy of LookPath in runutil, and changed code to
use the lookpath package instead.

Fixes v.io/i/1157

Change-Id: I21e2bbe7942abd52c27ed119adb6fc526d1f13fe
MultiPart: 2/3