gn/clang: Only pass -Wno-reserved-user-defined-literal on Linux and Android.

gn/clang: Only pass -Wno-reserved-user-defined-literal on Linux and Android.

This matches gyp. The flag is not needed on Windows and Mac.  (It probably isn't
needed on Android either.)

BUG=263960
Committed: https://crrev.com/64dff6deeae1788cdc60b5c02e82c527385dfe7a
Cr-Commit-Position: refs/heads/master@{#344275}

[Nico, 2015-08-17 22:52:45]

thakis@chromium.org changed reviewers:
+ brettw@chromium.org

[brettw, 2015-08-19 17:05:50]

LGTM. Sorry I didn't see this earlier.

[Nico, 2015-08-19 17:08:21]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-08-19 17:08:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1295023004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1295023004/1

[commit-bot: I haz the power, 2015-08-19 18:19:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-19 18:20:26]

Patchset 1 (id:??) landed as
https://crrev.com/64dff6deeae1788cdc60b5c02e82c527385dfe7a
Cr-Commit-Position: refs/heads/master@{#344275}