Declare virtual methods with empty body as pure virtual methods in rfb::CMsgHandler
class.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@3842 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/win/vncviewer/CConn.h b/win/vncviewer/CConn.h
index 726a6e8..bf7fd06 100644
--- a/win/vncviewer/CConn.h
+++ b/win/vncviewer/CConn.h
@@ -97,6 +97,7 @@
       CSecurity* getCSecurity(int secType);
       void setColourMapEntries(int firstColour, int nColours, rdr::U16* rgbs);
       void bell();
+      void framebufferUpdateStart() {}
       void framebufferUpdateEnd();
       void setDesktopSize(int w, int h);
       void setExtendedDesktopSize(int reason, int result, int w, int h,