fork: don't clear environment by default
fork: don't clear environment by default

- Set options.env to process.env instead of {} by default.
- Shallow clone the passed options.env in case the user passed process.env directly.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node