Building `FastAPI` with `buildroot` `2022.05` (with `flit`support) fails

[maovidal]

First Check

• [X] I added a very descriptive title to this issue.
• [X] I used the GitHub search to find a similar issue and didn't find it.
• [X] I searched the FastAPI documentation, with the integrated search.
• [X] I already searched in Google "How to X in FastAPI" and didn't find any information.
• [X] I already read and followed all the tutorial in the docs and didn't find an answer.
• [X] I already checked if it is not related to FastAPI but to Pydantic.
• [X] I already checked if it is not related to FastAPI but to Swagger UI.
• [X] I already checked if it is not related to FastAPI but to ReDoc.

Commit to Help

• [X] I commit to help with one of those options 👆

Example Code

Here are my two `Buildroot's` files for a package named `python-fastapi`:

[Config.in]
config BR2_PACKAGE_PYTHON_FASTAPI
	bool "python-fastapi"
	help
	  FastAPI framework, high performance, easy to learn, fast to code, ready for production

	  https://github.com/tiangolo/fastapi

[python-fastapi.mk]
################################################################################
#
# python-fastapi
#
################################################################################

PYTHON_FASTAPI_VERSION = 0.79.0
PYTHON_FASTAPI_SOURCE = fastapi-$(PYTHON_FASTAPI_VERSION).tar.gz
PYTHON_FASTAPI_SITE = https://files.pythonhosted.org/packages/ae/ed/ea37410618f1c206ba857d391d7b2de6de7a758ea586662aef77c945d3b4
PYTHON_FASTAPI_LICENSE = MIT
PYTHON_FASTAPI_LICENSE_FILES = LICENSE
PYTHON_FASTAPI_SETUP_TYPE = flit

$(eval $(python-package))

Description

The last 2022.05 version of buildroot has support to build python packages that use flit.

I don't know much about the details of how a python is packaged (and less about flit), but I understand that FastAPI provides a pyproject.toml file where the package details are contained.

I was able to successfully build the package once I changed this part of that file:

[build-system]
 requires = ["flit"]
 build-backend = "flit.buildapi"

To this one:

[build-system]
 requires = ["flit"]
 build-backend = "flit_core.buildapi"

But I'm not sure if that breaks it for someone else.

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.79.0

Python Version

3.10.4

Additional Context

No response