patch 8.0.0693: no terminal emulator support

Problem:    No terminal emulator support.  Cannot properly run commands in the
            GUI.  Cannot run a job interactively with an ssh connection.
Solution:   Very early implementation of the :terminal command.  Includes
            libvterm converted to ANSI C.  Many parts still missing.

src/config.mk.in

@@ -91,6 +91,8 @@ NETBEANS_SRC	= @NETBEANS_SRC@
 NETBEANS_OBJ	= @NETBEANS_OBJ@
 CHANNEL_SRC	= @CHANNEL_SRC@
 CHANNEL_OBJ	= @CHANNEL_OBJ@
+TERM_SRC	= @TERM_SRC@
+TERM_OBJ	= @TERM_OBJ@
 
 RUBY		= @vi_cv_path_ruby@
 RUBY_SRC	= @RUBY_SRC@