--- cpython-msys2/setup.py      2021-01-24 12:00:01.170000000 +0700
+++ cpython/setup.py    2021-01-24 10:50:57.710000000 +0700
@@ -51,7 +51,7 @@

 CROSS_COMPILING = ("_PYTHON_HOST_PLATFORM" in os.environ)
 HOST_PLATFORM = get_platform()
-MS_WINDOWS = (HOST_PLATFORM == 'win32')
+MS_WINDOWS = (HOST_PLATFORM == 'win32' or HOST_PLATFORM == 'mingw')
 CYGWIN = (HOST_PLATFORM == 'cygwin')
 MACOS = (HOST_PLATFORM == 'darwin')
 AIX = (HOST_PLATFORM.startswith('aix'))