kontrol build --rekompile fails with UnboundLocalError

[palinatolmach]

kontrol build --rekompile now fails with the following error:

❯ kontrol build --rekompile
WARNING 2023-10-26 23:46:47,176 kontrol.__main__ - Ignoring command-line option: -O0
WARNING 2023-10-26 23:46:47,176 kontrol.__main__ - Ignoring command-line option: -O1
WARNING 2023-10-26 23:46:47,176 kontrol.__main__ - Ignoring command-line option: -O2
WARNING 2023-10-26 23:46:47,176 kontrol.__main__ - Ignoring command-line option: -O3
Traceback (most recent call last):
  File "/nix/store/z1xa7anzsy9wrx9avy334zgv3p9xvaz8-python3.10-kontrol-0.1.37/bin/..kontrol-wrapped-wrapped", line 9, in <module>
    sys.exit(main())
  File "/nix/store/z1xa7anzsy9wrx9avy334zgv3p9xvaz8-python3.10-kontrol-0.1.37/lib/python3.10/site-packages/kontrol/__main__.py", line 71, in main
    execute(**vars(args))
  File "/nix/store/z1xa7anzsy9wrx9avy334zgv3p9xvaz8-python3.10-kontrol-0.1.37/lib/python3.10/site-packages/kontrol/__main__.py", line 130, in exec_build
    foundry_kompile(
  File "/nix/store/z1xa7anzsy9wrx9avy334zgv3p9xvaz8-python3.10-kontrol-0.1.37/lib/python3.10/site-packages/kontrol/kompile.py", line 148, in foundry_kompile
    plugin_dir=plugin_dir,
UnboundLocalError: local variable 'plugin_dir' referenced before assignment

kontrol build --rekompile --regen doesn't fail — it seems to be a bug introduced in #119, with plugin_dir = kdist.get('plugin') being set in an if-statement branch that doesn't get executed if only --rekompile is provided.