Makefile can compile KMK to MPY files

Dockerfile

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+FROM python:3.7-alpine
+
+RUN mkdir -p /app
+WORKDIR /app
+
+RUN apk update && apk add alpine-sdk curl gettext git git-lfs openssh rsync wget
+
+RUN pip install pipenv
+
+### Get a local copy of CircuitPython and its dependencies
+# Our absolute baseline is 4.0.0, which (as of writing) shares MPY compat
+# with all future versions. Our baseline will need to update as MPY compat
+# changes
+RUN git clone --branch 4.0.0 --depth 1 https://github.com/adafruit/CircuitPython /opt/circuitpython
+RUN git -C /opt/circuitpython submodule update --init
+
+### Build the MPY compiler
+RUN make -C /opt/circuitpython/mpy-cross
+
+ENV PATH=/opt/circuitpython/mpy-cross:${PATH}