Add Cygwin build test

.github/workflows/build.yml

@@ -87,3 +87,21 @@ jobs:
       - name: Run tests
         run: |
           ./build/hiredis-test.exe
+
+      - name: Setup cygwin
+        uses: egor-tensin/setup-cygwin@v3
+        with:
+          platform: x64
+          packages: cmake gcc-core gcc-g++
+
+      - name: Build in cygwin
+        env:
+          HIREDIS_PATH: ${{ github.workspace }}
+        run: |
+          build_hiredis() {
+              cd $(cygpath -u $HIREDIS_PATH)
+              rm -rf build && mkdir build && cd build
+              cmake .. -G "Unix Makefiles" && make VERBOSE=1
+          }
+          build_hiredis
+        shell: C:\tools\cygwin\bin\bash.exe --login --norc -eo pipefail -o igncr '{0}'