[New] build: CI: GitHub: Add Cygwin Makefile builder.

git-svn-id: https://source.openmpt.org/svn/openmpt/trunk/OpenMPT@22768 56274372-70c3-4bfc-bfc3-4c3a0b034d27

.github/workflows/Cygwin-Makefile.yml

@@ -0,0 +1,22 @@
+name: Cygwin Makefile
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cygwin/cygwin-install-action@master
+        with:
+          packages: subversion make gcc-core gcc-g++ autoconf autoconf-archive automake zlib-devel libmpg123-devel libogg-devel libvorbis-devel libsndfile-devel libflac-devel libSDL2-devel libportaudio-devel libportaudiocpp-devel libpulse-devel help2man doygen graphviz curl p7zip zip unzip perl-XML-XPath
+      - name: setup parallel make
+        run: bash -c 'echo MAKEFLAGS=-j${NUMBER_OF_PROCESSORS} >> $GITHUB_ENV'
+      - name: make
+        run: bash -c 'make'
+      - name: make check
+        run: bash -c 'make check'