Use msys2 instead of mingw

.travis.yml

@@ -1,6 +1,7 @@
 matrix:
   include:
 #    - os: linux
+#      name: linux
 #      language: java
 #      jdk: openjdk12
 #
@@ -67,6 +68,7 @@ matrix:
         - 'if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then bash ./macBuild-pure.sh; fi'
         - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then bash ./macBuildAndPublish-pure.sh; fi'
     - os: windows
+      name: windows
       language: shell
       jdk: openjdk12
       env:
@@ -74,6 +76,19 @@ matrix:
         - JAVA_OPTS=-Xmx2g
         - JDK="adopt-openj9@1.11"
       before_install:
+        - [[ ! -f C:/tools/msys64/msys2_shell.cmd ]] && rm -rf C:/tools/msys64
+            choco uninstall -y mingw
+            choco upgrade --no-progress -y msys2
+            export msys2='cmd //C RefreshEnv.cmd '
+            export msys2+='& set MSYS=winsymlinks:nativestrict '
+            export msys2+='& C:\\tools\\msys64\\msys2_shell.cmd -defterm -no-start'
+            export mingw64="$msys2 -mingw64 -full-path -here -c "\"\$@"\" --"
+            export msys2+=" -msys2 -c "\"\$@"\" --"
+            $msys2 pacman --sync --noconfirm --needed mingw-w64-x86_64-toolchain libtool automake
+            taskkill //IM gpg-agent.exe //F  # https://travis-ci.community/t/4967
+            export PATH=/C/tools/msys64/mingw64/bin:$PATH
+            export MAKE=mingw32-make  # so that Autotools can find it
+            ;;
         - curl "${GRAVIS}.install-jdk-travis.sh" --output ~/.install-jdk-travis.sh
         - source ~/.install-jdk-travis.sh
       script: