ci: Run on Linux arm64

Author: vadorovsky

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
 
   build:
     # We don't use ubuntu-latest because we care about the apt packages available.
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.platform.os }}
     strategy:
       fail-fast: false
       matrix:
@@ -64,15 +64,21 @@ jobs:
           - rust: nightly
             llvm: 21
             exclude-features: llvm-20,rust-llvm-20
+        platform:
+          - os: ubuntu-22.04
+          - os: ubuntu-22.04-arm
         llvm-from:
           - packages
         include:
+          # Currently we build LLVM from source only for Linux x86_64.
           - toolchain:
               rust: nightly
               llvm: 21
               exclude-features: llvm-20,rust-llvm-20
+            platform:
+              os: ubuntu-22.04
             llvm-from: source
-    name: rustc=${{ matrix.toolchain.rust }} llvm-version=${{ matrix.toolchain.llvm }} llvm-from=${{ matrix.llvm-from }}
+    name: os=${{ matrix.platform.os }} rustc=${{ matrix.toolchain.rust }} llvm-version=${{ matrix.toolchain.llvm }} llvm-from=${{ matrix.llvm-from }}
     needs: llvm
 
     env: