Fix compilation with MinGW32 or MinGW64 under Windows OS. Fixes #654

Thanks: hdeleau

Libs/Core/Testing/Cpp/CMakeLists.txt

@@ -110,7 +110,7 @@ if(HAVE_BFD)
   add_executable(ctkBinaryFileDescriptorTestHelper ctkBinaryFileDescriptorTestHelper.cpp)
 endif()
 
-if(WIN32)
+if(MSVC)
   add_definitions( /D _CRT_SECURE_NO_WARNINGS)
 endif()