Install bison and flex

Author: postgres-dev

.travis.yml

@@ -4,6 +4,20 @@ os:
 language: c
 
 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 "\"\$@"\" --"
+        $msys2 pacman --sync --noconfirm --needed mingw-w64-x86_64-toolchain bison flex
+        ## Install more MSYS2 packages from https://packages.msys2.org/base here
+        taskkill //IM gpg-agent.exe //F  # https://travis-ci.community/t/4967
+        export PATH=/C/tools/msys64/mingw64/bin:$PATH
+        export MAKE=mingw32-make  # so that Autotools can find it
     - git clone -b REL_14_STABLE --single-branch --depth 1 https://github.com/postgres/postgres.git
     - cd postgres/src/tools/msvc
     - cp config_default.pl config.pl