[linux] Use _GLIBCXX_DEBUG in Debug builds by default for better checking.

[linux] Use _GLIBCXX_DEBUG in Debug builds by default for better checking.

The _GLIBCXX_DEBUG macro is now set by default for Linux Debug builds
and can be disabled using the disable_glibcxx_debug=1
setting
(compatible with Chrome).  This will help us catch problems earlier.

BUG=v8:3638
LOG=n

Committed: https://crrev.com/b9513848873ef579e2023bdd728df27443fba55f
Cr-Commit-Position: refs/heads/master@{#26790}

[Benedikt Meurer, 2015-02-23 06:04:39]

bmeurer@chromium.org changed reviewers:
+ jarin@chromium.org

[Benedikt Meurer, 2015-02-23 06:04:40]

PTAL

[Jarin, 2015-02-23 06:11:58]

lgtm

[Jarin, 2015-02-23 06:12:01]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2015-02-23 06:12:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/946283003/1

[commit-bot: I haz the power, 2015-02-23 06:13:48]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 06:13:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 06:14:09]

Patchset 1 (id:??) landed as
https://crrev.com/b9513848873ef579e2023bdd728df27443fba55f
Cr-Commit-Position: refs/heads/master@{#26790}