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