Emit NS_NO_VTABLE in xpidl-generated interface files. NS_NO_VTABLE is defined in nsISupportsUtils.h, and on windows generates __declspec(novtable). This saves us some code space, and may also be a runtime win. Initial version of this fix courtesy Adam Lock <adamlock@netscape.com>. r=jband a=beard NOTE this change will cause the world to recompile. git-svn-id: svn://10.0.0.236/trunk@77200 18797224-902f-48f8-a5cc-f745e15eee43