ci: travis -> cirrus

.cirrus.yml

@@ -0,0 +1,44 @@
+env:
+  MAKEJOBS: "-j4"
+  RUN_TESTS: "true"
+  BASE_OUTDIR: "$CIRRUS_WORKING_DIR/out_dir_base"
+  DEBIAN_FRONTEND: "noninteractive"
+
+task:
+  container:
+    image: ubuntu:focal
+    cpu: 1
+    memory: 1G
+    greedy: true  # https://medium.com/cirruslabs/introducing-greedy-container-instances-29aad06dc2b4
+
+  matrix:
+    - name: "gcc"
+      env:
+        CC: "gcc"
+        CXX: "g++"
+        APT_PKGS: "gcc"
+    - name: "clang"
+      env:
+        CC: "clang"
+        CXX: "clang++"
+        APT_PKGS: "clang"
+    - name: "mingw"
+      env:
+        CC: ""
+        CXX: ""
+        UNIVALUE_CONFIG: "--host=x86_64-w64-mingw32"
+        APT_PKGS: "g++-mingw-w64-x86-64 gcc-mingw-w64-x86-64 binutils-mingw-w64-x86-64"
+        RUN_TESTS: "false"
+
+  install_script:
+    - apt update
+    - apt install -y pkg-config build-essential libtool autotools-dev automake bsdmainutils
+    - apt install -y $APT_PKGS
+  autogen_script:
+     - ./autogen.sh
+  configure_script:
+     - ./configure --cache-file=config.cache --bindir=$BASE_OUTDIR/bin --libdir=$BASE_OUTDIR/lib $UNIVALUE_CONFIG
+  make_script:
+     - make $MAKEJOBS V=1
+  test_script:
+     - if [ "$RUN_TESTS" = "true" ]; then make $MAKEJOBS distcheck; fi