Tweak -mssse3 on Mac a little.

Tweak -mssse3 on Mac a little.

Using OTHER_CPLUSPLUSFLAGS instead of OTHER_CFLAGS will append -mssse3 into the
argument list instead of overwriting as the old note warns about.  (So it's
actually there twice now for the files in opts_ssse3, and we can still build if
we remove -mssse3 from common_conditions.gypi.)

We could also just delete this clause entirely given that
common_conditions.gypi sets it anyway.  Which do you think is best?  This code
won't compile unless _someone_ has set -mssse3.  Seems to me the redundancy
helps communicate that and protect against changes in common_conditions.gypi.

BUG=

Committed: http://code.google.com/p/skia/source/detail?r=10573

[epoger, 2013-08-06 15:38:32]

Sorry for the late response...

https://codereview.chromium.org/21279005/diff/1/gyp/opts.gyp
File gyp/opts.gyp (right):

https://codereview.chromium.org/21279005/diff/1/gyp/opts.gyp#newcode130
gyp/opts.gyp:130: 'OTHER_CPLUSPLUSFLAGS': ['-mssse3',],
I don't understand how this is not susceptible to the same problem as
OTHER_CFLAGS.  If OTHER_CPLUSPLUSFLAGS has been set elsewhere, this will nuke
whatever settings were made to it...

Adding Ben Wagner as a reviewer, because I think he has a better understanding
of the issues than I do.  Ben, any clever ideas here?

[mtklein, 2013-08-06 15:50:39]

On 2013/08/06 15:38:32, epoger wrote:
> Sorry for the late response...
> 
> https://codereview.chromium.org/21279005/diff/1/gyp/opts.gyp
> File gyp/opts.gyp (right):
> 
> https://codereview.chromium.org/21279005/diff/1/gyp/opts.gyp#newcode130
> gyp/opts.gyp:130: 'OTHER_CPLUSPLUSFLAGS': ['-mssse3',],
> I don't understand how this is not susceptible to the same problem as
> OTHER_CFLAGS.  If OTHER_CPLUSPLUSFLAGS has been set elsewhere, this will nuke
> whatever settings were made to it...
> 
> Adding Ben Wagner as a reviewer, because I think he has a better understanding
> of the issues than I do.  Ben, any clever ideas here?

okay, please take another look.  just deleted it.

[epoger, 2013-08-06 15:51:56]

lgtm

[commit-bot: I haz the power, 2013-08-06 15:56:51]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/mtklein@google.com/21279005/5001

[commit-bot: I haz the power, 2013-08-06 18:13:04]

Change committed as 10573