Add (mostly Chromium-compatible) V8_OS_* defines to v8.gyp.

Add (mostly Chromium-compatible) V8_OS_* defines to v8.gyp.

R=jkummerow@chromium.org, svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16238

[Benedikt Meurer, 2013-08-19 09:10:06]

This is a first baby-step towards platform cleanup, instead of trying to do
everything at once as I did last time. The OS_* defines are mostly compatible
with what Chromium uses, which will allow for easier sharing/copying w/o
breakage on our side (i.e. the atomicops* stuff). It will also allow us to get
rid of a lot of fragile #ifdef'ery in the long term.

[Sven Panne, 2013-08-19 14:01:58]

LGTM, but perhaps Jakob might take a look, too...

[Jakob Kummerow, 2013-08-20 08:27:26]

LGTM.

As discussed offline, we might want to move this to build/features.gypi if other
targets need those defines as well, but doing so has other drawbacks, so let's
keep them in v8.gyp for now.

https://codereview.chromium.org/23283010/diff/5001/tools/gyp/v8.gyp
File tools/gyp/v8.gyp (right):

https://codereview.chromium.org/23283010/diff/5001/tools/gyp/v8.gyp#newcode791
tools/gyp/v8.gyp:791: 'V8_OS_BSD=1',
really?

[Benedikt Meurer, 2013-08-20 08:28:30]

https://codereview.chromium.org/23283010/diff/5001/tools/gyp/v8.gyp
File tools/gyp/v8.gyp (right):

https://codereview.chromium.org/23283010/diff/5001/tools/gyp/v8.gyp#newcode791
tools/gyp/v8.gyp:791: 'V8_OS_BSD=1',
On 2013/08/20 08:27:26, Jakob wrote:
> really?

Nope, copy&paste, fixed.

[Benedikt Meurer, 2013-08-20 08:29:34]

Committed patchset #3 manually as r16238.