Adds python. Closes compiler-explorer/python-builder#3 (#95)

Author: mattgodbolt

.github/workflows/build.yml

@@ -15,6 +15,7 @@ jobs:
         - lc3
         - misc
         - nasm
+        - python
         - pythran
         - rocm
         - rust-cg-gcc

Dockerfile.python

@@ -0,0 +1,22 @@
+FROM ubuntu:20.04
+
+# Enable source repositories so we can use `apt build-dep` to get all the
+# build dependencies for Python 3.5+.
+RUN sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list && \
+    sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
+
+ARG DEBIAN_FRONTEND=noninteractive
+RUN apt update -y -q && apt upgrade -y -q && apt update -y -q && \
+    apt -q build-dep -y python3.8 && \
+    apt -q install -y \
+    curl \
+    git \
+    libssl-dev \
+    unzip \
+    xz-utils
+
+RUN mkdir -p /root
+COPY python /root/
+COPY common.sh /root/
+
+WORKDIR /root

python/build.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+set -exu
+source common.sh
+
+ROOT=$(pwd)
+VERSION=$1
+FULLNAME=python-${VERSION}
+OUTPUT=${ROOT}/${FULLNAME}.tar.xz
+LAST_REVISION="${3:-}"
+
+if [[ -d "${2}" ]]; then
+   OUTPUT=$2/${FULLNAME}.tar.xz
+else
+   OUTPUT=${2-$OUTPUT}
+fi
+
+REVISION="python-${VERSION}"
+initialise "${REVISION}" "${OUTPUT}" "${LAST_REVISION}"
+
+DEST=/root/built
+
+curl -sL https://www.python.org/ftp/python/${VERSION}/Python-${VERSION}.tgz | tar zxf -
+pushd Python-${VERSION}
+./configure \
+    --prefix=${DEST} \
+    --enable-optimizations \
+    --without-pymalloc
+
+make -j$(nproc)
+make install
+popd
+
+# strip executables
+find ${DEST} -type f -perm /u+x -exec strip -d {} \;
+
+# delete tests and static libraries to save disk space
+find ${DEST} -type d -name test -exec rm -rf {} +
+find ${DEST} -type f -name *.a -delete
+
+complete "${DEST}" "${FULLNAME}" "${OUTPUT}"