ci: add GitHub Actions CI workflow

Author: thegushi

.github/workflows/ci.yml

@@ -0,0 +1,32 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install -y \
+            autoconf automake libtool pkg-config \
+            libmilter-dev \
+            lua5.4 liblua5.4-dev
+
+      - name: Bootstrap build system
+        run: autoreconf -fvi
+
+      - name: Configure
+        run: ./configure CFLAGS='-g -O2 -Wno-pointer-sign'
+
+      - name: Build
+        run: make -j$(nproc)