patch 8.1.0128: building with MinGW does not work out-of-the-box
Problem: Building with MinGW does not work out-of-the-box.
Solution: Add instructions for MSYS2. Set default WINVER. Add batch files
to set $PATH for MSYS2.
diff --git a/src/msys64.bat b/src/msys64.bat
new file mode 100755
index 0000000..dcfbbc9
--- /dev/null
+++ b/src/msys64.bat
@@ -0,0 +1,6 @@
+@echo off
+rem To be used on MS-Windows for Msys2 with the 64 bit MinGW compiler.
+rem Adjust the "c:\msys64" part to match your installation.
+@echo on
+
+set PATH=c:\msys64\mingw64\bin;c:\msys64\usr\bin;%PATH%