This change adds optional Dir string and Env []string options
that are passed through to the build system's metadata query.
As with exec.Cmd, the defaults are inherited from the parent
process.
Options.GOPATH is gone. If the client needs to override
GOPATH, they must use Env, but typically the inherited environment
is correct.
The tests not longer use os.Chdir.
We now guarantee that Package.Srcs are absolute file names.
Added test for Options.Dir and relative patterns.
This is a copy of golang.org/cl/123777, which had a merge conflict.
Change-Id: I301724581f3d8c712ea78fa5ab5cabd909940dca
Reviewed-on: https://go-review.googlesource.com/123777
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>