Our buildbot MacOS bot that builds Dartium is now failing, because the runhooks step that took 5 minutes is now taking more than 40 minutes.
The builder that is failing is https://uberchromegw.corp.google.com/i/client.dart/builders/dartium-mac-x64-inc-be


We are building Dartium based on Chrome 45, using gyp (I know, this is very very old, but it needs to work.  We are moving up to version 50 in weeks).

The bot runs, as part of the runhooks step, src/build/gyp_chromium' which took 303.54 secs

In the next build, and thereafter, the src/build/gyp_chromium step takes 40 minutes, and then the buildbot step times out.

Nothing changed in the dartium build, so I am wondering if software changes in the build directory maintained by chrome-infra could have caused this to happen.  The hash of the last working build directory release is
45191f3bfdf590993582f180df558b70d37ae710
and the first failing build directory release is 
04badb9796f8a7343ac7360203b367c1c976360b

We need to get this fixed somehow, so if someone with knowledge of gyp_chromium could help out, or from build or infra has any ideas, please help.