ninja win: Allow parent environment variables through when running actions

ninja win: Allow parent environment variables through when running actions

This is a hack to get variables set here:
https://code.google.com/p/chromium/codesearch#chromium/tools/build/scripts/slave/compile.py&l=416
through to version.py

In preference to https://codereview.chromium.org/136163002/ as it doesn't
involve trying to modify where the variables are set in master build
scripts.

TBR=thakis@chromium.org
BUG=333738
Committed: https://code.google.com/p/gyp/source/detail?r=1836

[scottmg, 2014-01-13 03:28:14]

This appears to work locally, so I'm going to TBR in an attempt to fix tonight's
Canary. I'll sort out something
more sane in the morning.

[scottmg, 2014-01-13 03:42:13]

Committed patchset #1 manually as r1836 (presubmit successful).

[Nico, 2014-01-14 02:10:02]

Hm, this doesn't seem so horrible to me. It's how linux and mac work too, no?
(except there aren't prebaked environments there, but you're only augmenting
those)

[scottmg, 2014-01-14 03:29:54]

On 2014/01/14 02:10:02, Nico wrote:
> Hm, this doesn't seem so horrible to me. It's how linux and mac work too, no?
> (except there aren't prebaked environments there, but you're only augmenting
> those)

That's right. It might be a bit confusing since e.g. PATH changes and other
things in the baked environment will be ignored, but other changes will make it
through.

Maybe not that big a deal though.