updated for version 7.4.562

Problem:    Segfault with wide screen and error in 'rulerformat'. (Ingo Karkat)
Solution:   Check there is enough space. (Christian Brabandt)

src/buffer.c

@@ -4409,6 +4409,8 @@ get_rel_pos(wp, buf, buflen)
     long	above; /* number of lines above window */
     long	below; /* number of lines below window */
 
+    if (buflen < 3) /* need at least 3 chars for writing */
+	return;
     above = wp->w_topline - 1;
 #ifdef FEAT_DIFF
     above += diff_check_fill(wp, wp->w_topline) - wp->w_topfill;