Add Alpine CI (#138)

[CI] [Alpine] Use dev version of Coq

From https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/57766#note_365103

.github/workflows/coq-alpine.yml

@@ -0,0 +1,122 @@
+name: CI (Coq, Alpine)
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+  merge_group:
+  workflow_dispatch:
+  release:
+    types: [published]
+  schedule:
+    - cron: '0 0 1 * *'
+
+jobs:
+  build:
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - alpine: 'edge'
+#        - alpine: 'latest-stable'
+
+    runs-on: ubuntu-latest
+    name: alpine-${{ matrix.alpine }}
+
+    concurrency:
+      group: ${{ github.workflow }}-alpine-${{ matrix.alpine }}-${{ github.head_ref || github.run_id }}
+      cancel-in-progress: true
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: recursive
+    - name: host build params
+      run: etc/ci/describe-system-config.sh
+    - uses: jirutka/setup-alpine@v1
+      with:
+        branch: ${{ matrix.alpine }}
+        extra-repositories: https://dl-cdn.alpinelinux.org/alpine/edge/testing
+        packages: git make jq gcc musl-dev python3 ocaml ocaml-findlib ghc cabal coq ocaml-zarith bash
+    # next two steps as per https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/57766#note_365103
+    - name: Download development Coq
+      shell: alpine.sh {0}
+      run: |
+        mkdir -p MR
+        wget 'https://gitlab.alpinelinux.org/JasonGross/aports/-/jobs/1224462/artifacts/download?file_type=archive' -O MR.zip
+        unzip MR.zip -d MR
+        ls -la MR
+        find MR
+    - name: Set up development Coq
+      shell: alpine.sh --root {0}
+      run: |
+        mv MR/keys/*.pub /etc/apk/keys/
+        echo '::group::cat /etc/apk/repositories'
+        cat /etc/apk/repositories
+        echo '::endgroup::'
+        printf '\n' >> /etc/apk/repositories
+        ls -d "$(pwd)"/MR/packages/* >> /etc/apk/repositories
+        echo '::group::cat /etc/apk/repositories'
+        cat /etc/apk/repositories
+        echo '::endgroup::'
+        apk update
+        apk add --upgrade coq
+    - name: chroot build params
+      shell: alpine.sh {0}
+      run: etc/ci/describe-system-config.sh
+    - name: explore
+      shell: alpine.sh {0}
+      run: |
+        echo '::group::apk list --installed'
+        apk list --installed
+        echo '::endgroup::'
+        for pkg in coq dune ocaml-ppxlib; do
+          echo "::group::apk info -L $pkg"
+          apk info -L $pkg
+          echo '::endgroup::'
+        done
+        for f in $(find MR/packages -name "*.apk"); do
+          echo "::group::file $f"
+          file $f || echo $?
+          echo '::endgroup::'
+          echo "::group::tar --warning=no-unknown-keyword -tvf $f"
+          tar --warning=no-unknown-keyword -tvf $f || echo $?
+          echo '::endgroup::'
+        done
+        which coqc
+        dirname "$(which coqc)"
+        echo '::group::ocamlfind list'
+        ocamlfind list
+        echo '::endgroup::'
+        echo '::group::ocamlc -where'
+        ocamlc -where
+        echo '::endgroup::'
+        for q in findlib zarith ppxlib dune coq coq-core coq-core.plugins coq-core.plugins.ltac; do
+          echo "::group::ocamlfind query $q"
+          ocamlfind query $q || echo $?
+          echo '::endgroup::'
+          echo "::group::ocamlfind query $q | xargs find"
+          ( ocamlfind query $q | xargs find ) || echo $?
+          echo '::endgroup::'
+        done
+    - name: make all
+      shell: alpine.sh {0}
+      run: etc/ci/github-actions-make.sh ALLOW_DIFF=1 -j2 all
+    - name: make perf-Sanity
+      shell: alpine.sh {0}
+      run: etc/ci/github-actions-make.sh ALLOW_DIFF=1 -j2 perf-Sanity
+    - name: display timing info
+      run: cat time-of-build-pretty.log
+    - name: display per-line timing info
+      run: etc/ci/github-actions-display-per-line-timing.sh
+
+  alpine-check-all:
+    runs-on: ubuntu-latest
+    needs: [build]
+    if: always()
+    steps:
+    - run: echo 'build passed'
+      if: ${{ needs.build.result == 'success' }}
+    - run: echo 'build failed' && false
+      if: ${{ needs.build.result != 'success' }}