feat(google-crc32c): add riscv64 manylinux wheel builds

Add riscv64 to the manylinux wheel build matrix using the
manylinux_2_39_riscv64 image (the correct tag for riscv64; manylinux2014
has no riscv64 variant).

Changes:
- scripts/manylinux/build.sh: add riscv64 docker run block
- .github/workflows/riscv64-wheels.yml: CI workflow to build and upload
  riscv64 wheels on pull_request/push to main

The build uses QEMU emulation on ubuntu-latest, matching the approach
used for the existing aarch64 builds.

Follows up on googleapis/python-crc32c#337 (closed when repo was
archived; maintainer asked to re-open here).

Signed-off-by: Bruno Verachten <gounthar@gmail.com>

Author: gounthar

packages/google-crc32c/.github/workflows/riscv64-wheels.yml

@@ -0,0 +1,47 @@
+name: "Build riscv64 wheels"
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - 'packages/google-crc32c/**'
+  push:
+    branches:
+      - main
+    paths:
+      - 'packages/google-crc32c/**'
+
+permissions:
+  contents: read
+
+jobs:
+  build-riscv64:
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up QEMU
+        # v4.0.0
+        uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a
+        with:
+          platforms: riscv64
+
+      - name: Build riscv64 wheels
+        env:
+          WORKSPACE: ${{ github.workspace }}
+        run: |
+          IMAGE=quay.io/pypa/manylinux_2_39_riscv64
+          VOLUME="${WORKSPACE}/packages/google-crc32c:/var/code/python-crc32c/"
+          docker pull "${IMAGE}"
+          docker run --rm --volume "${VOLUME}" "${IMAGE}" \
+            /var/code/python-crc32c/scripts/manylinux/build_on_centos.sh
+
+      - name: Upload wheels
+        uses: actions/upload-artifact@v4
+        with:
+          name: riscv64-wheels
+          path: packages/google-crc32c/wheels/

packages/google-crc32c/scripts/manylinux/build.sh

@@ -52,6 +52,15 @@ docker run \
     quay.io/pypa/manylinux2014_aarch64 \
     /var/code/python-crc32c/scripts/manylinux/build_on_centos.sh
 
+docker pull quay.io/pypa/manylinux_2_39_riscv64
+docker run \
+    --rm \
+    --interactive \
+    --volume ${REPO_ROOT}:/var/code/python-crc32c/ \
+    --env BUILD_PYTHON=${BUILD_PYTHON} \
+    quay.io/pypa/manylinux_2_39_riscv64 \
+    /var/code/python-crc32c/scripts/manylinux/build_on_centos.sh
+
 if [[ "${PUBLISH_WHEELS}" == "true" ]]; then
     . /${MANYLINUX_DIR}/publish_python_wheel.sh
 fi