patch 8.1.2281: 'showbreak' cannot be set for one window

Problem:    'showbreak' cannot be set for one window.
Solution:   Make 'showbreak' global-local.
diff --git a/src/move.c b/src/move.c
index d6b1c26..484b931 100644
--- a/src/move.c
+++ b/src/move.c
@@ -988,6 +988,8 @@
 	/* long line wrapping, adjust curwin->w_wrow */
 	if (curwin->w_wcol >= curwin->w_width)
 	{
+	    char_u *sbr;
+
 	    /* this same formula is used in validate_cursor_col() */
 	    n = (curwin->w_wcol - curwin->w_width) / width + 1;
 	    curwin->w_wcol -= n * width;
@@ -997,8 +999,9 @@
 	    /* When cursor wraps to first char of next line in Insert
 	     * mode, the 'showbreak' string isn't shown, backup to first
 	     * column */
-	    if (*p_sbr && *ml_get_cursor() == NUL
-		    && curwin->w_wcol == (int)vim_strsize(p_sbr))
+	    sbr = get_showbreak_value(curwin);
+	    if (*sbr && *ml_get_cursor() == NUL
+				    && curwin->w_wcol == (int)vim_strsize(sbr))
 		curwin->w_wcol = 0;
 #endif
 	}