Encoding: Support building on Windows with WIN32_LEAN_AND_MEAN

Include the <shellapi.h> header to get CommandLineToArgvW even
when <windows.h> does not include it due to WIN32_LEAN_AND_MEAN.

Change-Id: If42241621c30b76c7b49cd64e044a19403f9da09

EncodingCXX.cxx

@@ -38,6 +38,7 @@
 // Windows API.
 #if defined(_WIN32)
 # include <windows.h>
+# include <shellapi.h>
 #endif
 
 namespace KWSYS_NAMESPACE