patch 8.2.1898: command modifier parsing always uses global cmdmod

Problem:    Command modifier parsing always uses global cmdmod.
Solution:   Pass in cmdmod_T to use.  Rename struct fields consistently.
diff --git a/src/quickfix.c b/src/quickfix.c
index 5e0d3c3..ac95ace 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -2834,7 +2834,7 @@
     win_T	*wp;
     int		flags;
 
-    if (cmdmod.tab != 0 || newwin)
+    if (cmdmod.cmod_tab != 0 || newwin)
 	wp = NULL;
     else
 	wp = qf_find_help_win();
@@ -2845,7 +2845,7 @@
 	// Split off help window; put it at far top if no position
 	// specified, the current window is vertically split and narrow.
 	flags = WSP_HELP;
-	if (cmdmod.split == 0 && curwin->w_width != Columns
+	if (cmdmod.cmod_split == 0 && curwin->w_width != Columns
 		&& curwin->w_width < 80)
 	    flags |= WSP_TOP;
 	// If the user asks to open a new window, then copy the location list.
@@ -3278,7 +3278,8 @@
     qfltype_T	qfl_type = qfl->qfl_type;
 
     // For ":helpgrep" find a help window or open one.
-    if (qf_ptr->qf_type == 1 && (!bt_help(curwin->w_buffer) || cmdmod.tab != 0))
+    if (qf_ptr->qf_type == 1 && (!bt_help(curwin->w_buffer)
+						      || cmdmod.cmod_tab != 0))
 	if (jump_to_help_window(qi, newwin, opened_window) == FAIL)
 	    return FAIL;
     if (old_qf_curlist != qi->qf_curlist
@@ -4125,12 +4126,12 @@
     // The current window becomes the previous window afterwards.
     win = curwin;
 
-    if (IS_QF_STACK(qi) && cmdmod.split == 0)
+    if (IS_QF_STACK(qi) && cmdmod.cmod_split == 0)
 	// Create the new quickfix window at the very bottom, except when
 	// :belowright or :aboveleft is used.
 	win_goto(lastwin);
     // Default is to open the window below the current window
-    if (cmdmod.split == 0)
+    if (cmdmod.cmod_split == 0)
 	flags = WSP_BELOW;
     flags |= WSP_NEWLOC;
     if (win_split(height, flags) == FAIL)
@@ -4208,9 +4209,9 @@
 #endif
 
     // Find an existing quickfix window, or open a new one.
-    if (cmdmod.tab == 0)
+    if (cmdmod.cmod_tab == 0)
 	status = qf_goto_cwindow(qi, eap->addr_count != 0, height,
-						cmdmod.split & WSP_VERT);
+						cmdmod.cmod_split & WSP_VERT);
     if (status == FAIL)
 	if (qf_open_new_cwindow(qi, height) == FAIL)
 	{
@@ -5693,7 +5694,7 @@
 
     enc = (*curbuf->b_p_menc != NUL) ? curbuf->b_p_menc : p_menc;
 #ifdef FEAT_BROWSE
-    if (cmdmod.browse)
+    if (cmdmod.cmod_flags & CMOD_BROWSE)
     {
 	char_u *browse_file = do_browse(0, (char_u *)_("Error file"), eap->arg,
 				   NULL, NULL,
@@ -6164,7 +6165,7 @@
 		    wipe_dummy_buffer(buf, dirname_start);
 		    buf = NULL;
 		}
-		else if (!cmdmod.hide
+		else if ((cmdmod.cmod_flags & CMOD_HIDE) == 0
 			    || buf->b_p_bh[0] == 'u'	// "unload"
 			    || buf->b_p_bh[0] == 'w'	// "wipe"
 			    || buf->b_p_bh[0] == 'd')	// "delete"