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- [x] Add new / update outdated documentation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: ruamel.yaml
  version: 0.17.21
  top-level:
    - ruamel
source:
  url: https://files.pythonhosted.org/packages/9e/cb/938214ac358fbef7058343b3765c79a1b7ed0c366f7f992ce7ff38335652/ruamel.yaml-0.17.21-py3-none-any.whl
  sha256: 742b35d3d665023981bd6d16b3d24248ce5df75fdb4e2924e93a05c1f8b61ca7
test:
  imports:
    - ruamel.yaml
about:
  home: https://sourceforge.net/p/ruamel-yaml/code/ci/default/tree
  PyPI: https://pypi.org/project/ruamel.yaml
  summary:
    ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation
    of comments, seq/map flow style, and map key order
  license: MIT license

package:
  name: ruamel.yaml
  version: 0.17.21
  top-level:
    - ruamel
source:
  url: https://files.pythonhosted.org/packages/9e/cb/938214ac358fbef7058343b3765c79a1b7ed0c366f7f992ce7ff38335652/ruamel.yaml-0.17.21-py3-none-any.whl
  sha256: 742b35d3d665023981bd6d16b3d24248ce5df75fdb4e2924e93a05c1f8b61ca7
test:
  imports:
    - ruamel.yaml
about:
  home: https://sourceforge.net/p/ruamel-yaml/code/ci/default/tree
  PyPI: https://pypi.org/project/ruamel.yaml
  summary:
    ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation
    of comments, seq/map flow style, and map key order
  license: MIT license
