Build python 3.9 and switch to GitHub Actions (#3)

.github/workflows/build.yml

@@ -0,0 +1,33 @@
+name: build
+on: [push, pull_request]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [ 3.6.12, 3.7.9, 3.8.6, 3.9.0 ]
+        arch: [ amd64, aarch64 ]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup QEMU
+        if: matrix.arch != 'amd64'
+        uses: docker/setup-qemu-action@v1
+        with:
+          platforms: all
+      - name: Setup Docker buildx
+        if: matrix.arch != 'amd64'
+        uses: docker/setup-buildx-action@v1
+        with:
+          install: true
+      - name: Download docker image
+        run: docker pull dmoj/runtimes-tier1:${{ matrix.arch }}-latest
+      - name: Build python
+        run: |
+          PYTHON_DIR="python$(echo "${{ matrix.python-version }}" | cut -d. -f 1-2)"
+          PYTHON_URL="https://www.python.org/ftp/python/$(perl -e 'shift=~/([\d.]+)/;print$1' "${{ matrix.python-version }}")/Python-${{ matrix.python-version }}.tar.xz"
+          docker run -e ARCH="${{ matrix.arch }}" -e PYTHON_DIR="$PYTHON_DIR" -e PYTHON_URL="$PYTHON_URL" -v "$(pwd):/code" dmoj/runtimes-tier1:${{ matrix.arch }}-latest
+      - name: Archive build artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: Python ${{ matrix.python-version }} (${{ matrix.arch }})
+          path: python*.tar.gz

run

@@ -7,7 +7,7 @@ mkdir "$PYTHON_DIR"
 echo "Downloading $PYTHON_URL to $PYTHON_DIR..."
 curl -L "$PYTHON_URL" | tar -xJ -C "$PYTHON_DIR" --strip-components=1
 cd "$PYTHON_DIR"
-./configure --prefix=/code/"$PYTHON_DIR" --enable-optimizations
+./configure --prefix=/code/"$PYTHON_DIR" $(if [ "$ARCH" = amd64 -a "$(echo "$PYTHON_DIR" | cut -d. -f2)" -ge 8 ]; then echo --enable-optimizations; fi)
 make -j"$(nproc)"
 make install
 cd /code && tar czvf "$PYTHON_DIR-$ARCH.tar.gz" "$PYTHON_DIR"