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- [x] Add new / update outdated documentation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: cffi
  version: 1.15.1
  top-level:
    - cffi
requirements:
  run:
    - pycparser
source:
  url: https://files.pythonhosted.org/packages/2b/a8/050ab4f0c3d4c1b8aaa805f70e26e84d0e27004907c5b8ecc1d31815f92a/cffi-1.15.1.tar.gz
  sha256: d400bfb9a37b1351253cb402671cea7e89bdecc294e8016a707f6d1d8ac934f9
  patches:
    - patches/libffi-config.patch
build:
  cross-build-env: true
about:
  home: http://cffi.readthedocs.org
  PyPI: https://pypi.org/project/cffi
  summary: Foreign Function Interface for Python calling C code.
  license: MIT

package:
  name: cffi
  version: 1.15.1
  top-level:
    - cffi
requirements:
  run:
    - pycparser
source:
  url: https://files.pythonhosted.org/packages/2b/a8/050ab4f0c3d4c1b8aaa805f70e26e84d0e27004907c5b8ecc1d31815f92a/cffi-1.15.1.tar.gz
  sha256: d400bfb9a37b1351253cb402671cea7e89bdecc294e8016a707f6d1d8ac934f9
  patches:
    - patches/libffi-config.patch
build:
  cross-build-env: true
about:
  home: http://cffi.readthedocs.org
  PyPI: https://pypi.org/project/cffi
  summary: Foreign Function Interface for Python calling C code.
  license: MIT
