Deb builder for extpython

Build process:

• ./build.sh to kick off the process, runs a docker image - docker run -it --rm -v $PWD:/src ubuntu:bionic bash
  • ./build-inner.sh called in the container, prepares the environment
  • ./build-inner.sh switches to an underpriv'd user and calls...
    • ./build-deb.sh - does the actual build

TODO:

• parameterize the build:
  • vars.sh needs to pass PYTHON_RELEASE down into the makefile
  • debian metadata files need to obey this too:
    • changelog: package name and version
    • control: package name
    • Makefile: a component of the --prefix path

TODO later:

• upload resulting deb to artifact
• support other than Bionic
• separate process into creating the builder image & building the deb itself
• parameter for pre-loaded pip modules