ENH: add processor type of win32

Modules/CMakeDetermineSystem.cmake

@@ -37,7 +37,7 @@ ELSE(UNIX)
   IF(WIN32)
     SET (CMAKE_SYSTEM_NAME "Windows")
     SET (CMAKE_SYSTEM_VERSION "")  
-    SET (CMAKE_SYSTEM_PROCESSOR "")
+    SET (CMAKE_SYSTEM_PROCESSOR "$ENV{PROCESSOR_ARCHITECTURE}")
   ENDIF(WIN32)
 ENDIF(UNIX)