Reland initial bits of "Implement correct OS and CC detection."

Reland initial bits of "Implement correct OS and CC detection."

This adds the OS and CC detection and cleans up the globals.h to
some degree. It also places all of the C++11 feature detection into
globals.h.

R=svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=15953

[Benedikt Meurer, 2013-07-30 08:50:31]

First part of the OS/CC detection change.

[Sven Panne, 2013-07-30 10:34:18]

LGTM. May the build bots be with you! :-)

[Benedikt Meurer, 2013-07-30 10:37:03]

Committed patchset #1 manually as r15953 (presubmit successful).