Self Docker builder

Build container image

Preconditions

Install and set up Docker CE. See https://docs.docker.com/get-started/.
Deep clone https://github.com/watson-intu/self.git to a convenient and capacious filesystem location; you will later set the make variable self_DIR during the build process so keep the path handy.

Steps

Create a self image with an invocation like this:
```
 make self_DIR=$HOME/projects/self all
```

If you do not already have them available, this will build a self-docker-builder-i build image, run that image as a self-docker-builder container, compile the self source, extract the build artifacts, and create a slimmer runtime container with self inside it. If you want to perform just some of the above steps, consult the Makefile for targets you might run.

Note that if you invoke a make target that builds a Docker container without specifying DOCKERB_OPTS or DOCKERE_OPTS, Docker will ignore all cached build layers (for the build container and execution container respectively). To override this and get some work saving benefit, invoke make with the option DOCKERB_OPTS="".

Build the self project with a command like:

 docker exec -it self-docker-builder /self/scripts/build.sh linux

Other options

To get more build output from make, set the VERBOSE=y build option.

Cleanup

When you're finished with the build container and image, you can execute make self_DIR=$HOME/projects/self distclean in this project directory and clean up docker and other artifacts from the build process. Note that if you used Docker efficiencies when building, there may be extra, untagged Docker images on your system. Consult the Docker documentation for information on deleting such images.

Known problems

The build process for non-x86 boxes fails
Documentation of all build features is lacking