- Fork LibBar on Github, apply patch
     - In docker stage build-bar:
        - RUN git clone gh.com/my_org/bar
        - WORKDIR bar/build
        - RUN cmake .. -DCMAKE_BUILD_TYPE=Release (old habits die hard, need to remember to use -B)
        - RUN make -j
     - in main docker stage: --mount from=bar,src=bar/build,target=/tmp/bar make install

The python case is thankfully usually not terrible nowadays (clone, `uv build`, push to artifact registry), modulo needing to pass whatever flag to uv to let it take into account both my private registry and public pypi at the same time.

    1: Clone gh.com/someone/LibBar to gh.com/me/LibBar
    2: Fix the bug
    3: Send pull request to someone
    5: git submodule set-url lib/LibBar https://gh.com/me/LibBar.git
       git submodule sync lib/LibBar
       git submodule update --init --remote --recursive lib/LibBar
       cd lib/LibBar/; git checkout main; cd ../..
       git add .; git commit -m "Use my own version of lib/LibBar"

It thought that this was option #2 but apparently no