ENH: Adding definition of MSVC when it is the compiler.

Modules/Platform/Windows-cl.cmake

@@ -4,6 +4,7 @@ INCLUDE( ${CMAKE_BINARY_DIR}/CMakeFiles/CMakeCPlatform.cmake OPTIONAL)
 SET(CMAKE_LIBRARY_PATH_FLAG "-LIBPATH:")
 SET(CMAKE_LINK_LIBRARY_FLAG "")
 SET(WIN32 1)
+SET(MSVC 1)
 IF(CMAKE_VERBOSE_MAKEFILE)
   SET(CMAKE_CL_NOLOGO)
 ELSE(CMAKE_VERBOSE_MAKEFILE)