Differentiate build artifacts generated between MinGW and VS.

[cache clear]

CMakeLists.txt

@@ -109,6 +109,9 @@ elseif (IOS)
 elseif (APPLE)
     set (CPACK_SYSTEM_NAME OSX)
 elseif (WIN32)
+    if (MINGW)
+        set (CPACK_SYSTEM_NAME MinGW)   # MinGW implies Windows platform
+    endif ()
     set (CPACK_GENERATOR ZIP)
 elseif (WEB)
     set (CPACK_SYSTEM_NAME Web)