diff -Naur newton-dynamics-3.14c.orig/CMakeLists.txt newton-dynamics-3.14c/CMakeLists.txt
--- newton-dynamics-3.14c.orig/CMakeLists.txt	2020-05-03 00:08:37.000000000 +0200
+++ newton-dynamics-3.14c/CMakeLists.txt	2020-11-30 20:53:38.420522700 +0100
@@ -154,7 +154,7 @@
 	message("CMAKE_CXX_FLAGS_RELEASE is ${CMAKE_CXX_FLAGS_RELEASE}")
 elseif(MINGW)
 	add_compile_options(-msse3)
-	if(CMAKE_CL_64)
+	if(BUILD_64)
 		message("build 64 bit")
 		add_definitions(-D_MINGW_64_VER)
 		add_definitions(-D_WIN_64_VER)
