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- [x] Add new / update outdated documentation

# pyodide.ffi

```{eval-rst}
.. currentmodule:: pyodide.ffi

.. automodule:: pyodide.ffi
   :members:
   :autosummary:
   :autosummary-no-nesting:
   :show-inheritance:

.. automodule:: pyodide.ffi.wrappers
   :members:
   :autosummary:
   :autosummary-no-nesting:
```

# pyodide.ffi

```{eval-rst}
.. currentmodule:: pyodide.ffi

.. automodule:: pyodide.ffi
   :members:
   :autosummary:
   :autosummary-no-nesting:
   :show-inheritance:

.. automodule:: pyodide.ffi.wrappers
   :members:
   :autosummary:
   :autosummary-no-nesting:
```
