add 32-bit CI config

.github/workflows/ci.yml

@@ -4,19 +4,34 @@ on:
   - pull_request
 jobs:
   build:
+    name: ${{ matrix.name }}
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os:
-          - ubuntu-22.04
-          - macos-12
-          - windows-2022
+        include:
+          - name: "Linux x64 (Ubuntu 22.04)"
+            os: ubuntu-22.04
+            config: {}
+          - name: "Linux 32-bit (Ubuntu 22.04)"
+            os: ubuntu-22.04
+            config: { cflags: "-m32"}
+          - name: "macOS 12"
+            os: macos-12
+            config: {}
+          - name: "Windows 2022"
+            os: windows-2022
+            config: {}
+    env:
+      CFLAGS: ${{ matrix.config.cflags }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
       - name: Dependencies (ubuntu)
         if: contains(matrix.os, 'ubuntu')
         run: sudo apt update && sudo apt install -y gifsicle valgrind meson
+      - name: Dependencies (ubuntu 32-bit)
+        if: contains(matrix.name, '32-bit')
+        run: sudo apt update && sudo apt install -y gcc-multilib libc6-dbg:i386
       - name: Dependencies (macos)
         if: contains(matrix.os, 'macos')
         run: brew install gifsicle meson