ninja: Reduce size of individual_generated_bindings by another 45kB / 15%.

1. Only write unique_name for rules on Windows, it's unused elsewhere.
Makes individual_generated_bindings.ninja another 30kB / 10% smaller.

2. Don't include the hash in the rule name: It's not needed since the stamp
file has a qualified path. Saves another 14kB.

BUG=350317
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/206153004

git-svn-id: http://gyp.googlecode.com/svn/trunk@1880 78cadc50-ecff-11dd-a971-7dbc132099af
Fix ARCHS selection when building for iOS

When building for iOS, consider any architecture set in the gyp files
as valid (to allow building for x86_64 when using Xcode 4.0 or higher).

BUG=webrtc:3073
R=thakis@chromium.org

Review URL: https://codereview.chromium.org/203763002

git-svn-id: http://gyp.googlecode.com/svn/trunk@1881 78cadc50-ecff-11dd-a971-7dbc132099af