BLD Add DISTDIR variable. ### Description

Adds `DISTDIR` env variable that points to the directory where libraries should be copied to when building shared libraries with recipe.

### Checklists

- [x] Add new / update outdated documentation

package:
  name: parso
  version: 0.8.3
  top-level:
    - parso
source:
  sha256: c001d4636cd3aecdaf33cbb40aebb59b094be2a74c556778ef5576c175e19e75
  url: https://files.pythonhosted.org/packages/05/63/8011bd08a4111858f79d2b09aad86638490d62fbf881c44e434a6dfca87b/parso-0.8.3-py2.py3-none-any.whl
about:
  home: https://github.com/davidhalter/parso
  PyPI: https://pypi.org/project/parso
  summary: A Python Parser
  license: MIT

package:
  name: parso
  version: 0.8.3
  top-level:
    - parso
source:
  sha256: c001d4636cd3aecdaf33cbb40aebb59b094be2a74c556778ef5576c175e19e75
  url: https://files.pythonhosted.org/packages/05/63/8011bd08a4111858f79d2b09aad86638490d62fbf881c44e434a6dfca87b/parso-0.8.3-py2.py3-none-any.whl
about:
  home: https://github.com/davidhalter/parso
  PyPI: https://pypi.org/project/parso
  summary: A Python Parser
  license: MIT
