Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
Unvendor distutils. Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
package:
  name: pillow
  version: 8.0.1
source:
  sha256: 11c5c6e9b02c9dac08af04f093eb5a2f84857df70a7d4a6a6ad461aca803fb9e
  url: https://files.pythonhosted.org/packages/2b/06/93bf1626ef36815010e971a5ce90f49919d84ab5d2fa310329f843a74bc1/Pillow-8.0.1.tar.gz

  patches:
   - patches/setitup.patch
  extras:
   -
      - src/setup.cfg
      - ./setup.cfg
build:
  cflags: -s USE_ZLIB=1 -s USE_LIBJPEG=1 -s USE_FREETYPE=1
  ldflags: -s USE_LIBJPEG=1 -s USE_FREETYPE=1 -ljpeg
test:
  imports:
  - PIL

package:
  name: pillow
  version: 8.0.1
source:
  sha256: 11c5c6e9b02c9dac08af04f093eb5a2f84857df70a7d4a6a6ad461aca803fb9e
  url: https://files.pythonhosted.org/packages/2b/06/93bf1626ef36815010e971a5ce90f49919d84ab5d2fa310329f843a74bc1/Pillow-8.0.1.tar.gz

  patches:
   - patches/setitup.patch
  extras:
   -
      - src/setup.cfg
      - ./setup.cfg
build:
  cflags: -s USE_ZLIB=1 -s USE_LIBJPEG=1 -s USE_FREETYPE=1
  ldflags: -s USE_LIBJPEG=1 -s USE_FREETYPE=1 -ljpeg
test:
  imports:
  - PIL
