Add macos and windows to CI.

Author: silene

.github/workflows/ci.yml

@@ -14,3 +14,19 @@ jobs:
       run: g++ -Wall -W -O2 remake.cpp -o remake
     - name: test
       run: ./remake check
+
+  build-macos:
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: build
+      run: clang++ -Wall -W -O2 remake.cpp -o remake
+    - name: test
+      run: ./remake check
+
+  build-windows:
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: build
+      run: g++ -Wall -W -O2 remake.cpp -o remake -lws2_32