diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4a01386..e886b64 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -9,16 +9,26 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest     # x86_64 Linux
+          - ubuntu-24.04-arm  # ARM64 Linux
+          - macos-15-intel    # Intel macOS
+          - macos-latest      # ARM64 macOS
+          - windows-latest    # x86_64 Windows
+    runs-on: ${{ matrix.os }}
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v5
 
-    - name: Set up GNAT toolchain
-      run: >
-        sudo apt-get update && 
-        sudo apt-get install gnat gprbuild
+    - name: Set up Alire
+      uses: alire-project/setup-alire@v5
 
-    - name: Build
-      run: gprbuild -j0 -p
+    - name: Build project
+      run: alr build
+
+    - name: Run tests
+      run: alr test
diff --git a/src/c.c b/src/c.c
index f808a2c..4ecdf44 100644
--- a/src/c.c
+++ b/src/c.c
@@ -1,3 +1,4 @@
+#include <sys/types.h> // Needed on macOS to get FILE definition early
 #include <stdio.h>
 
 void sl_flush_stdout(void) {