Remove nsIDocumentViewer.h from EXPORTS. It does not live here. Thanks to 'David Gardiner' <david.gardiner@unisa.edu.au> for the patch.

webshell/public/makefile.win

@@ -28,7 +28,6 @@ EXPORTS =                               \
         nsIDocumentLoader.h             \
         nsIDocumentLoaderObserver.h     \
         nsIDocStreamLoaderFactory.h     \
-        nsIDocumentViewer.h             \
         nsILinkHandler.h                \
         nsIThrobber.h                   \
         nsIWebShell.h                   \