patch 8.0.1566: too many #ifdefs

Problem:    Too many #ifdefs.
Solution:   Graduate FEAT_SCROLLBIND and FEAT_CURSORBIND.

src/diff.c

@@ -1160,16 +1160,12 @@ diff_win_options(
 # endif
 
     /* Use 'scrollbind' and 'cursorbind' when available */
-#ifdef FEAT_SCROLLBIND
     if (!wp->w_p_diff)
 	wp->w_p_scb_save = wp->w_p_scb;
     wp->w_p_scb = TRUE;
-#endif
-#ifdef FEAT_CURSORBIND
     if (!wp->w_p_diff)
 	wp->w_p_crb_save = wp->w_p_crb;
     wp->w_p_crb = TRUE;
-#endif
     if (!wp->w_p_diff)
 	wp->w_p_wrap_save = wp->w_p_wrap;
     wp->w_p_wrap = FALSE;
@@ -1199,10 +1195,8 @@ diff_win_options(
     /* make sure topline is not halfway a fold */
     changed_window_setting_win(wp);
 # endif
-#ifdef FEAT_SCROLLBIND
     if (vim_strchr(p_sbo, 'h') == NULL)
 	do_cmdline_cmd((char_u *)"set sbo+=hor");
-#endif
     /* Save the current values, to be restored in ex_diffoff(). */
     wp->w_p_diff_saved = TRUE;
 
@@ -1221,9 +1215,7 @@ diff_win_options(
 ex_diffoff(exarg_T *eap)
 {
     win_T	*wp;
-#ifdef FEAT_SCROLLBIND
     int		diffwin = FALSE;
-#endif
 
     FOR_ALL_WINDOWS(wp)
     {
@@ -1237,14 +1229,10 @@ ex_diffoff(exarg_T *eap)
 	    if (wp->w_p_diff_saved)
 	    {
 
-#ifdef FEAT_SCROLLBIND
 		if (wp->w_p_scb)
 		    wp->w_p_scb = wp->w_p_scb_save;
-#endif
-#ifdef FEAT_CURSORBIND
 		if (wp->w_p_crb)
 		    wp->w_p_crb = wp->w_p_crb_save;
-#endif
 		if (!wp->w_p_wrap)
 		    wp->w_p_wrap = wp->w_p_wrap_save;
 #ifdef FEAT_FOLDING
@@ -1276,20 +1264,16 @@ ex_diffoff(exarg_T *eap)
 	    /* Note: 'sbo' is not restored, it's a global option. */
 	    diff_buf_adjust(wp);
 	}
-#ifdef FEAT_SCROLLBIND
 	diffwin |= wp->w_p_diff;
-#endif
     }
 
     /* Also remove hidden buffers from the list. */
     if (eap->forceit)
 	diff_buf_clear();
 
-#ifdef FEAT_SCROLLBIND
     /* Remove "hor" from from 'scrollopt' if there are no diff windows left. */
     if (!diffwin && vim_strchr(p_sbo, 'h') != NULL)
 	do_cmdline_cmd((char_u *)"set sbo-=hor");
-#endif
 }
 
 /*