Error building wheel

What went wrong?

Pip was trying to build the project using wheel and errored with this output:

Collecting gssapi
  Using cached gssapi-1.8.2.tar.gz (94 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  ERROR: Command errored out with exit status 1:
   command: /home/mason/BeehiveAPIBackend/venv/bin/python3 /tmp/tmp5g4xky0b get_requires_for_build_wheel /tmp/tmpmot9xp07
       cwd: /tmp/pip-install-l5by33hj/gssapi
  Complete output (21 lines):
  /bin/sh: 1: krb5-config: not found
  Traceback (most recent call last):
    File "/tmp/tmp5g4xky0b", line 280, in <module>
      main()
    File "/tmp/tmp5g4xky0b", line 263, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "/tmp/tmp5g4xky0b", line 114, in get_requires_for_build_wheel
      return hook(config_settings)
    File "/tmp/pip-build-env-7dhst_op/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 341, in get_requires_for_build_wheel
      return self._get_build_requires(config_settings, requirements=['wheel'])
    File "/tmp/pip-build-env-7dhst_op/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 323, in _get_build_requires
      self.run_setup()
    File "/tmp/pip-build-env-7dhst_op/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 338, in run_setup
      exec(code, locals())
    File "<string>", line 109, in <module>
    File "<string>", line 22, in get_output
    File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
      return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
    File "/usr/lib/python3.8/subprocess.py", line 516, in run
      raise CalledProcessError(retcode, process.args,
  subprocess.CalledProcessError: Command 'krb5-config --libs gssapi' returned non-zero exit status 127.
  ----------------------------------------
ERROR: Command errored out with exit status 1: /home/mason/BeehiveAPIBackend/venv/bin/python3 /tmp/tmp5g4xky0b get_requires_for_build_wheel /tmp/tmpmot9xp07 Check the logs for full command output.

How do we reproduce?

(Remember to use fenced code blocks and consider placing in a gist if large)

Set up a python venv

Install the following requirements from requirements.txt (I haven't been able to determine which one python-gssapi is a dependency of):

connexion >= 2.6.0
connexion[swagger-ui] >= 2.6.0
python_dateutil == 2.6.0
setuptools >= 21.0.0
swagger-ui-bundle >= 0.0.2
mysql-connector-python>=8.0.32
arcgis>=2.0.0

Component versions (python-gssapi, Kerberos, OS / distro, etc.)

(Please include MIT/Heimdal/etc. and how you installed python-gssapi)

Installed via pip 20.0.2 from a requirements.txt file containing the contents mentioned above. Using Ubuntu 20.04.5 LTS. Attempting to install python-gssapi 1.8.2. I know my cached version isn't corrupted because this happened on the first try after pip downloaded the package.

Reproduce the failure on Ubuntu 20.04.5 with the listed requirements and pip 20.0.2, starting with the python-gssapi 1.8.2 wheel-build output. Investigate why krb5-config is unavailable during the build and determine whether the dependency or installation guidance needs correction. Done means the requirements install succeeds or the required prerequisite is clearly documented.