Be explicit about not wanting a trigraph.

Be explicit about not wanting a trigraph.

Both cl.exe and clang-cl don't use trigraphs on Windows by default, but
clang still warns about them.  Since the standard does include trigraphs,
fix the code to not (accidentally) include a trigraph rather than siliencing
the warning.

BUG=82385
Committed: https://crrev.com/34fead5eae3de03b4b63acbdbe8491f75e353232
Cr-Commit-Position: refs/heads/master@{#309526}

[Nico, 2014-12-23 00:09:08]

thakis@chromium.org changed reviewers:
+ cpu@chromium.org, forshaw@chromium.org

[cpu_(ooo_6.6-7.5), 2014-12-23 01:59:32]

lgtm

so we can't use raw strings yet?

[Nico, 2014-12-23 02:02:28]

On 2014/12/23 01:59:32, cpu (ooo till jan 5) wrote:
> lgtm
> 
> so we can't use raw strings yet?

Would that help? I thought trigraphs are handled before tokenizing. After a
short search,
http://stackoverflow.com/questions/6855149/are-trigraph-substitutions-reverte...
seems to back that up. It appears that raw strings are only just mostly raw.

[Nico, 2014-12-23 02:02:32]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2014-12-23 02:03:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/822813003/20001

[commit-bot: I haz the power, 2014-12-23 02:50:39]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-12-23 02:51:35]

Patchset 2 (id:??) landed as
https://crrev.com/34fead5eae3de03b4b63acbdbe8491f75e353232
Cr-Commit-Position: refs/heads/master@{#309526}

[Nico, 2014-12-30 21:44:26]

On 2014/12/23 02:02:28, Nico wrote:
> On 2014/12/23 01:59:32, cpu (ooo till jan 5) wrote:
> > lgtm
> > 
> > so we can't use raw strings yet?
> 
> Would that help? I thought trigraphs are handled before tokenizing. After a
> short search,
>
http://stackoverflow.com/questions/6855149/are-trigraph-substitutions-reverte...
> seems to back that up. 

(Mostly note to self: [lex.pptoken]p3 does say that trigraphs are reverted back
in raw strings. This just doesn't happen if the raw string is built by
token-pasting, which is the case in that stack overflow post.)