Add ninja generator flag for writing library deps.

This adds a flag to the ninja generator to specify a file to write library
deps to as generation proceeds. This is so GN can suck the deps out.

BUG=288991
Review=https://codereview.chromium.org/23601020/


git-svn-id: http://gyp.googlecode.com/svn/trunk@1723 78cadc50-ecff-11dd-a971-7dbc132099af
Add cpu_limit to ninja link pool on windows.

This will cap the number of links at the min of cpu_count v. mem / 4G.

R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/24106005

git-svn-id: http://gyp.googlecode.com/svn/trunk@1724 78cadc50-ecff-11dd-a971-7dbc132099af
ninja windows: VS2013 improvements

- Use vs2013 x64->x86 cross compiler if available
- Add /FS compiler flag which maintains previous version PDB behavior.

R=thakis@chromium.org
BUG=chromium:288948

Review URL: https://codereview.chromium.org/23447022

git-svn-id: http://gyp.googlecode.com/svn/trunk@1725 78cadc50-ecff-11dd-a971-7dbc132099af
ninja/mac: Try to fix 'IOError: [Errno 2] No such file or directory' error.

Happening on this Blink bot:
http://chromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Mac%20Builder%20%28dbg%29

This probably broke when we changed the generator to write ninja files after
their contents are known -- because of that the folder doesn't exist yet
when the per-arch files are written.

R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/23533053

git-svn-id: http://gyp.googlecode.com/svn/trunk@1726 78cadc50-ecff-11dd-a971-7dbc132099af
Add an environment variable to specify the hard cap on the number of concurrent linkers in gyp/ninja/windows.

The core count was a poor abstraction of this. Since we can't easily+accurately model the bottleneck, expose the cap as an environment variable so we can tweak it on the bots as necessary.

The default hard cap is 2**32. I'm assuming that we'll never need that many concurrent links.

R=thakis@chromium.org

Review URL: https://codereview.chromium.org/23995007

git-svn-id: http://gyp.googlecode.com/svn/trunk@1727 78cadc50-ecff-11dd-a971-7dbc132099af