Closes https://github.com/pyodide/pyodide/issues/604

This creates an installable `pyodide-build` Python package that we can also upload to PyPi under https://pypi.org/project/pyodide-build/ (currently uploaded the dev version to reserve the name).

There is also the identically named `pyodide-build` CLI command which replaces `bin/pyodide`.

The short term goals is to use fewer hacks with `PATH` and `PYTHONPATH`. Long term goal make it a user facing interface for building packages instead of the Makefile.
Create an installable pyodide-build package. Closes https://github.com/pyodide/pyodide/issues/604

This creates an installable `pyodide-build` Python package that we can also upload to PyPi under https://pypi.org/project/pyodide-build/ (currently uploaded the dev version to reserve the name).

There is also the identically named `pyodide-build` CLI command which replaces `bin/pyodide`.

The short term goals is to use fewer hacks with `PATH` and `PYTHONPATH`. Long term goal make it a user facing interface for building packages instead of the Makefile.
package:
  name: decorator
  version: 5.0.6
source:
  sha256: f2e71efb39412bfd23d878e896a51b07744f2e2250b2e87d158e76828c5ae202
  url: https://files.pythonhosted.org/packages/6a/aa/c194bd2fb168c1ebd8ffbfc12d972d09a9df0e4d485013e5ba2c8e4f1f05/decorator-5.0.6.tar.gz
test:
  imports:
  - decorator

package:
  name: decorator
  version: 5.0.6
source:
  sha256: f2e71efb39412bfd23d878e896a51b07744f2e2250b2e87d158e76828c5ae202
  url: https://files.pythonhosted.org/packages/6a/aa/c194bd2fb168c1ebd8ffbfc12d972d09a9df0e4d485013e5ba2c8e4f1f05/decorator-5.0.6.tar.gz
test:
  imports:
  - decorator
