Install Sail from binary in CI

This should be a lot faster. It also means the version is pinned properly which wasn't the case before.

I also recommended users to do the same in the README do they don't have to deal with OPAM.

.github/workflows/compile.yml

@@ -7,19 +7,19 @@ jobs:
  runs-on: ubuntu-22.04
  steps:
  - name: Install packages
- run: sudo apt install -y opam zlib1g-dev pkg-config libgmp-dev z3 device-tree-compiler
+ run: sudo apt install -y --no-install-recommends opam zlib1g-dev pkg-config libgmp-dev device-tree-compiler curl
  - name: Check out repository code
  uses: actions/checkout@HEAD
  with:
  submodules: true
  - name: Ensure pre-commit checks pass
  run: pip install pre-commit && pre-commit run --all-files --show-diff-on-failure --color=always
- - name: Init opam
- run: opam init --disable-sandboxing -y
- - name: Install sail
- run: opam install -y sail
+ - name: Install sail from binary
+ run: |
+  sudo mkdir -p /usr/local
+  curl --location https://github.com/rems-project/sail/releases/download/0.18-linux-binary/sail.tar.gz | sudo tar xvz --directory=/usr/local --strip-components=1
  - name: Build and test simulators
- run: eval $(opam env) && test/run_tests.sh
+ run: test/run_tests.sh
  - name: Upload test results
  if: always()
  uses: actions/upload-artifact@v4

README.md

@@ -275,7 +275,7 @@ Getting started
 
 ### Building the model
 
-Install [Sail](https://github.com/rems-project/sail/) [using opam](https://github.com/rems-project/sail/blob/sail2/INSTALL.md) then:
+Install [Sail](https://github.com/rems-project/sail/). On Linux you can download a [binary release](https://github.com/rems-project/sail/releases) (strongly recommended), or you can install from source [using opam](https://github.com/rems-project/sail/blob/sail2/INSTALL.md). Then:
 
 ```
 $ make