I am facing the same problem:
2023-11-28 13:47:31,439: DEBUG - Collecting mysqlclient
2023-11-28 13:47:31,440: DEBUG - Using cached mysqlclient-2.2.0.tar.gz (89 kB)
2023-11-28 13:47:31,457: DEBUG - Installing build dependencies: started
2023-11-28 13:47:33,296: DEBUG - Installing build dependencies: finished with status 'done'
2023-11-28 13:47:33,297: DEBUG - Getting requirements to build wheel: started
2023-11-28 13:47:33,416: DEBUG - Getting requirements to build wheel: finished with status 'error'
2023-11-28 13:47:33,416: WARNING - ERROR: Command errored out with exit status 1:
2023-11-28 13:47:33,417: WARNING - command: /opt/yunohost/seafile/venv/bin/python3 /tmp/tmpjk6jklvu_in_process.py get_requires_for_build_wheel /tmp/tmp8njc0l1j
2023-11-28 13:47:33,417: WARNING - cwd: /tmp/pip-install-aklkg3l4/mysqlclient_065fbd3a4dac42839933e1d784d912cb
2023-11-28 13:47:33,417: WARNING - Complete output (24 lines):
2023-11-28 13:47:33,417: WARNING - /bin/sh: 1: pkg-config: not found
2023-11-28 13:47:33,418: WARNING - /bin/sh: 1: pkg-config: not found
2023-11-28 13:47:33,418: WARNING - Trying pkg-config --exists mysqlclient
2023-11-28 13:47:33,418: WARNING - Command 'pkg-config --exists mysqlclient' returned non-zero exit status 127.
2023-11-28 13:47:33,418: WARNING - Trying pkg-config --exists mariadb
2023-11-28 13:47:33,419: WARNING - Command 'pkg-config --exists mariadb' returned non-zero exit status 127.
2023-11-28 13:47:33,419: WARNING - Traceback (most recent call last):
2023-11-28 13:47:33,419: WARNING - File "/tmp/tmpjk6jklvu_in_process.py", line 280, in <module>
2023-11-28 13:47:33,419: WARNING - main()
2023-11-28 13:47:33,420: WARNING - File "/tmp/tmpjk6jklvu_in_process.py", line 263, in main
2023-11-28 13:47:33,420: WARNING - json_out['return_val'] = hook(**hook_input['kwargs'])
2023-11-28 13:47:33,420: WARNING - File "/tmp/tmpjk6jklvu_in_process.py", line 114, in get_requires_for_build_wheel
2023-11-28 13:47:33,420: WARNING - return hook(config_settings)
2023-11-28 13:47:33,421: WARNING - File "/tmp/pip-build-env-mlkv3z8m/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 325, in get_requires_for_build_wheel
2023-11-28 13:47:33,421: WARNING - return self._get_build_requires(config_settings, requirements=['wheel'])
2023-11-28 13:47:33,421: WARNING - File "/tmp/pip-build-env-mlkv3z8m/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 295, in _get_build_requires
2023-11-28 13:47:33,421: WARNING - self.run_setup()
2023-11-28 13:47:33,421: WARNING - File "/tmp/pip-build-env-mlkv3z8m/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 311, in run_setup
2023-11-28 13:47:33,422: WARNING - exec(code, locals())
2023-11-28 13:47:33,422: WARNING - File "<string>", line 154, in <module>
2023-11-28 13:47:33,422: WARNING - File "<string>", line 48, in get_config_posix
2023-11-28 13:47:33,422: WARNING - File "<string>", line 27, in find_package_name
2023-11-28 13:47:33,423: WARNING - Exception: Can not find valid pkg-config name.
2023-11-28 13:47:33,423: WARNING - Specify MYSQLCLIENT_CFLAGS and MYSQLCLIENT_LDFLAGS env vars manually
2023-11-28 13:47:33,423: WARNING - ----------------------------------------
2023-11-28 13:47:33,423: WARNING - WARNING: Discarding https://files.pythonhosted.org/packages/de/9c/b176826e8994551ce826404dab97e305a4bb76c8b0a4e016fabda2901c71/mysqlclient-2.2.0.tar.gz#sha256=04368445f9c487d8abb7a878e3d23e923e6072c04a6c320f9e0dc8a82efba14e (from https://pypi.org/simple/mysqlclient/) (requires-python:>=3.8). Command errored out with exit status 1: /opt/yunohost/seafile/venv/bin/python3 /tmp/tmpjk6jklvu_in_process.py get_requires_for_build_wheel /tmp/tmp8njc0l1j Check the logs for full command output.
WARNING - touch: cannot touch '#action,port,logpath,etc)inthatsectionwithinjail.local'$'\n''#Changelogpathwithyourfilelogusedbyseafile(e.g.seahub.log)'$'\n''/opt/yunohost/seafile/logs/seahub.log': No such file or directory