To support console.log when using dust server-side (e.g. node.js), I would declare a var outside of dust.log as follows:

```javascript
// no-op logger by default
var log = function() {};

// Try to find the console logger in window scope (browsers) or top level scope (node.js)
if (typeof window !== 'undefined' && window && window.console && window.console.log) {
  log = window.console.log;
} else if (typeof console !== 'undefined' && console && console.log) {
  log = console.log;
}
```