Various GN fixes.

Various GN fixes.

- Fixes gcc_version issues on gTrusty.
- Fixes accidental duplicate in input_events build file.
- Fixes spammy warnings in libxml.

BUG=none
TEST=builds

Committed: https://crrev.com/54d9265014bce6db79a5a0364031e29e031c8d26
Cr-Commit-Position: refs/heads/master@{#292669}

[DaleCurtis, 2014-08-28 23:05:20]

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

[brettw, 2014-08-29 16:15:58]

lgtm

[DaleCurtis, 2014-08-29 17:01:55]

The CQ bit was checked by dalecurtis@chromium.org

[commit-bot: I haz the power, 2014-08-29 17:02:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dalecurtis@chromium.org/518543004/1

[commit-bot: I haz the power, 2014-08-29 18:04:01]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[commit-bot: I haz the power, 2014-08-29 18:08:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-29 18:08:19]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[DaleCurtis, 2014-08-29 18:10:21]

dalecurtis@chromium.org changed reviewers:
+ jamesr@chromium.org

[DaleCurtis, 2014-08-29 18:10:21]

+jamesr for mojo

[jamesr, 2014-08-29 18:18:26]

lgtm

[DaleCurtis, 2014-08-29 18:21:18]

The CQ bit was checked by dalecurtis@chromium.org

[commit-bot: I haz the power, 2014-08-29 18:22:31]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dalecurtis@chromium.org/518543004/1

[commit-bot: I haz the power, 2014-08-29 18:28:02]

Committed patchset #1 (id:1) as cd8c43eeef1f335eacd108b544e403df98135314

[commit-bot: I haz the power, 2014-09-10 03:10:01]

Patchset 1 (id:??) landed as
https://crrev.com/54d9265014bce6db79a5a0364031e29e031c8d26
Cr-Commit-Position: refs/heads/master@{#292669}