Memory issue with large array for ignore_dirs

I'd like to ignore all but one of 1200 directories in the `node_modules` for an Ember.js (node) application.

I added the 1199 directories to the `ignore_dirs` array in `.watchmanconfig`, and when I try to boot up my app, the watchman process starts eating all of my system memory, and eventually fails.


Everything works fine when `ignore_dirs` does not include any children of `node_modules`, but then it's watching 120 000
files unnecessarily, and I often need to have several apps running at once, and system limits become an issue.