patch 8.0.1610: cannot build without GUI

Problem:    Cannot build without GUI.
Solution:   Add #ifdef.

src/terminal.c

@@ -2735,6 +2735,7 @@ term_line2screenline(VTermScreen *screen, VTermPos *pos, int max_col)
     }
 }
 
+#if defined(FEAT_GUI)
     static void
 update_system_term(term_T *term)
 {
@@ -2777,6 +2778,7 @@ update_system_term(term_T *term)
     term->tl_dirty_row_end = 0;
     update_cursor(term, TRUE);
 }
+#endif
 
 /*
  * Called to update a window that contains an active terminal.

src/version.c

@@ -766,6 +766,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1610,
 /**/
     1609,
 /**/