patch 8.0.0651: build failure without the auto command feature

Problem:    Build failure without the auto command feature.
Solution:   Add #ifdef. (closes #1782)

src/ex_cmds.c

@@ -6832,9 +6832,11 @@ fix_help_buffer(void)
     char_u	*rt;
     int		mustfree;
 
+#ifdef FEAT_AUTOCMD
     /* Set filetype to "help" if still needed. */
     if (STRCMP(curbuf->b_p_ft, "help") != 0)
 	set_option_value((char_u *)"ft", 0L, (char_u *)"help", OPT_LOCAL);
+#endif
 
 #ifdef FEAT_SYN_HL
     if (!syntax_present(curwin))

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    651,
 /**/
     650,
 /**/