Mac OS El Capitan (10.11) blocking npm install, what to do?

The last version of Mac OS X, El Capitan (version 10.11), is sometimes blocking npm install. For exemple, if you want to install ios-deploy for Cordova with the following command, you will get an error message:

This will return something like this:

To prevent this error, you will need to add --unsafe-perm=true as parameter, which is preventing Mac OS X to block unsafe commands (of course, use it only with trusted plugins).

It will show the following message, but your plugin will successfully install :