hashdist/hashdist — pull request #294 by ahmadia (2014-12-05 00:20:30+00:00)
Title: Add update mode

This mode allows a user to append to nodes in the YAML file.

This can be useful when programmatically building up a set of configure
commands, for example, instead of resorting to a Python hook file.

Example use:

```
- when: pyver == '3.4'
name: configure
mode: update
extra: ['--without-ensurepip']

- when: python_framework
name: configure
mode: update
extra: ['--enable-framework=${ARTIFACT}']
```