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/ex_docmd.c

@@ -488,6 +488,9 @@ static void	ex_folddo(exarg_T *eap);
 #ifndef FEAT_PROFILE
 # define ex_profile		ex_ni
 #endif
+#ifndef FEAT_TERMINAL
+# define ex_terminal		ex_ni
+#endif
 
 /*
  * Declare cmdnames[].