Build static Linux arm64 binaries without docker (#6928)

Author: cknitt

.github/workflows/ci.yml

@@ -89,49 +89,6 @@ jobs:
           name: rewatch-${{env.artifact_dir_name}}
           path: ${{ env.artifact_dir_name }}
 
-  # Build statically linked Linux binaries in an Alpine-based Docker container
-  # See https://ocamlpro.com/blog/2021_09_02_generating_static_and_portable_executables_with_ocaml
-  # for more info.
-  # The container already comes with all required tools pre-installed
-  # (see https://github.com/rescript-lang/docker-rescript-ci-build/blob/main/Dockerfile).
-  # Note: Static ARM64 binaries cannot be built directly on Ubuntu runner because of
-  # https://github.com/ocaml/opam-repository/issues/26216
-  build-compiler-linux-arm:
-    runs-on: buildjet-2vcpu-ubuntu-2204-arm
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Build compiler binaries
-        uses: docker://ghcr.io/rescript-lang/rescript-ci-build:alpine-3.20-ocaml-5.2.0-01
-        with:
-          args: opam exec -- dune build --display quiet --profile static
-
-      - name: Build ninja binary
-        uses: docker://ghcr.io/rescript-lang/rescript-ci-build:alpine-3.20-ocaml-5.2.0-01
-        with:
-          args: sh -c "cd ninja && LDFLAGS=-static python configure.py --bootstrap"
-
-      - name: Use Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: 18
-
-      - name: Get artifact dir name
-        run: node .github/workflows/get_artifact_dir_name.js
-
-      - name: Copy exes to platform bin dir
-        run: |
-          node ./scripts/copyExes.js -compiler
-          node ./scripts/copyExes.js -ninja
-
-      - name: "Upload artifacts: binaries"
-        uses: actions/upload-artifact@v4
-        with:
-          name: binaries-${{ env.artifact_dir_name }}
-          path: ${{ env.artifact_dir_name }}
-
   build-compiler:
     strategy:
       fail-fast: false
@@ -143,6 +100,9 @@ jobs:
             upload_libs: true
             # Build the playground compiler on the fastest runner
             build_playground: true
+          - os: buildjet-2vcpu-ubuntu-2204-arm # ARM
+            ocaml_compiler: ocaml-variants.5.2.0+options,ocaml-option-static
+            upload_binaries: true
           - os: macos-13 # x64
             ocaml_compiler: 5.2.0
             upload_binaries: true
@@ -224,6 +184,8 @@ jobs:
         uses: ocaml/[email protected]
         if: steps.cache-opam-env.outputs.cache-hit != 'true'
         with:
+          opam-repositories: |
+            default: https://github.com/rescript-lang/opam-repository.git
           ocaml-compiler: ${{matrix.ocaml_compiler}}
           opam-pin: false
 
@@ -422,7 +384,6 @@ jobs:
   package:
     needs:
       - build-compiler
-      - build-compiler-linux-arm
       - build-rewatch
 
     runs-on: ubuntu-latest