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- [x] Add new / update outdated documentation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: pyparsing
  version: 3.0.9
  top-level:
    - pyparsing
source:
  sha256: 5026bae9a10eeaefb61dab2f09052b9f4307d44aee4eda64b309723d8d206bbc
  url: https://files.pythonhosted.org/packages/6c/10/a7d0fa5baea8fe7b50f448ab742f26f52b80bfca85ac2be9d35cdd9a3246/pyparsing-3.0.9-py3-none-any.whl

package:
  name: pyparsing
  version: 3.0.9
  top-level:
    - pyparsing
source:
  sha256: 5026bae9a10eeaefb61dab2f09052b9f4307d44aee4eda64b309723d8d206bbc
  url: https://files.pythonhosted.org/packages/6c/10/a7d0fa5baea8fe7b50f448ab742f26f52b80bfca85ac2be9d35cdd9a3246/pyparsing-3.0.9-py3-none-any.whl
