mac: Followup to ZERO_AR_DATE, touch the -o archive, rather than expecting only one

mac: Followup to ZERO_AR_DATE, touch the -o archive, rather than expecting only one

After https://codereview.chromium.org/791993005/.

When multiarch, libtool is run as "... -o foo.a foo.i386.a foo.x86_64.a"
so previously the touch wouldn't happen. Instead, look for the -o, and
touch that archive.

Add ARCHS to test to exercise this.

R=sebmarchand@chromium.org, thakis@chromium.org
BUG=451499
Committed: https://code.google.com/p/gyp/source/detail?r=2029

[scottmg, 2015-01-28 21:38:09]

scottmg@chromium.org changed reviewers:
+ maruel@chromium.org

[scottmg, 2015-01-28 21:38:36]

scottmg@chromium.org changed reviewers:
- maruel@chromium.org

[Sébastien Marchand, 2015-01-28 21:43:45]

LGTM. Thanks for fixing my bugs. I'm not so familiar with OS X etc, so you might
want for Nico to review this before landing it.

[Nico, 2015-01-28 22:29:59]

lgtm, thanks!

[scottmg, 2015-01-29 18:22:17]

Committed patchset #2 (id:20001) manually as 2029 (presubmit successful).

[scottmg, 2015-01-29 18:23:13]

On 2015/01/29 18:22:17, scottmg wrote:
> Committed patchset #2 (id:20001) manually as 2029 (presubmit successful).

Wow! Committing to gyp: definitely Computer Science's hardest problem.