Related to sequelize/sequelize#5438 and sequelize/sequelize#5476.

var pg = require('pg')
_.clone(pg);

Throws Error: Cannot find module 'pg-native'

Wanting to clone the library directly doesn't make much sense, but in the issues linked above, it happens because a sequelize model, which has a reference to pg is being deeply cloned.

This should be fixable by switching to defineProperty and marking the native property as non-enumerable.

I can write up a PR later today if you'd like - I just need a hint as to where to put the test