ENH: make sure msvc90 gets set

Modules/Platform/Windows-cl.cmake.in

@@ -7,6 +7,7 @@ SET(MSVC60 @MSVC60@)
 SET(MSVC70 @MSVC70@)
 SET(MSVC71 @MSVC71@)
 SET(MSVC80 @MSVC80@)
+SET(MSVC90 @MSVC90@)
 SET(MSVC_IDE @MSVC_IDE@)
 SET(MSVC_VERSION @MSVC_VERSION@)
 SET(WIN32 1)