Effectively unlimited linking.

Ninja will still cap concurrency with it's default value (from -j), so we just
need a big number equal or greater than the number of cores in any machine.

BUG=skia:
R=borenet@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/319153002
diff --git a/gyp_skia b/gyp_skia
index 040253e..be90916 100755
--- a/gyp_skia
+++ b/gyp_skia
@@ -134,6 +134,11 @@
       os.environ[ENVVAR_GYP_GENERATOR_FLAGS] = (
           gyp_generator_flags + ' msvs_error_on_missing_sources=1')
 
+  # GYP is very conservative about how many concurrent linker calls it allows,
+  # to fit in RAM. We don't need to be nearly as conservative as Chrome.  We'll
+  # just turn that feature off.
+  os.environ['GYP_LINK_CONCURRENCY'] = '9001'
+
   print 'Updating projects from gyp files...'
   sys.stdout.flush()