os/exec: API

[rsc]

In the BUG note about OS X, s/extra/unwanted/?  The field is already named extra.

Add Waitmsg to struct, so that it can be consulted after a successful exit.
(Will need to replace Waitmsg with something more portable, but that's a
different bug; using os.Waitmsg for now, we'll find it later.)

[bradfitz]

Comment 1:

http://golang.org/cl/5655048

Owner changed to @bradfitz.

[bradfitz]

Comment 2:

This issue was closed by revision 5d198bf.

Status changed to Fixed.