For OS X 10.12
If you get this error when installing the npm package canvas
$ npm install canvas
npm WARN gentlyRm not removing /Users/simon/repos/mac-setup/node_modules/.bin/rimraf as it wasn't installed by /Users/simon/repos/mac-setup/node_modules/rimraf
> canvas@1.6.6 install /Users/simon/repos/mac-setup/node_modules/canvas
> node-gyp rebuild