slow scripts/tools startup

[jordens]

The entry point scripts are really slow on a regular python installation. The pkg_resources mechanism scans the complete python path multiple times.

This seems to be pypa/setuptools#510

Maybe involved in #407 but then again maybe not because we pool the workers.

[sbourdeauducq]

fastentrypoints breaks the new-style conda noarch package (and the old style noarch breaks entry points on Windows with recent conda, resulting in a "Failed to create process" error).
This only slows down the startup of ARTIQ programs when started by the user from the command line. Everywhere else, including in worker startup, subprocess creation is done with sys.executable + " -m artiq.xxx" so as to depend as little as possible on the packaging system.

[sbourdeauducq]

Doesn't seem to be an issue anymore.

• Nix and Conda have their own Python startup scripts that don't use pkg_resources.
• MSYS2 uses recent setuptools with easy_install that only uses pkg_resources at last resort (https://github.com/pypa/setuptools/blob/main/setuptools/command/easy_install.py#L2089-L2095)