patch 8.0.1498: getjumplist() returns duplicate entries

Problem:    Getjumplist() returns duplicate entries. (lacygoill)
Solution:   Call cleanup_jumplist(). (Yegappan Lakshmanan)
diff --git a/src/proto/mark.pro b/src/proto/mark.pro
index ff1f441..aa6f44e 100644
--- a/src/proto/mark.pro
+++ b/src/proto/mark.pro
@@ -9,6 +9,7 @@
 pos_T *getmark(int c, int changefile);
 pos_T *getmark_buf_fnum(buf_T *buf, int c, int changefile, int *fnum);
 pos_T *getnextmark(pos_T *startpos, int dir, int begin_line);
+void fname2fnum(xfmark_T *fm);
 void fmarks_check_names(buf_T *buf);
 int check_mark(pos_T *pos);
 void clrallmarks(buf_T *buf);
@@ -23,6 +24,7 @@
 void mark_col_adjust(linenr_T lnum, colnr_T mincol, long lnum_amount, long col_amount);
 void copy_jumplist(win_T *from, win_T *to);
 void free_jumplist(win_T *wp);
+void cleanup_jumplist(win_T *wp);
 void set_last_cursor(win_T *win);
 void free_all_marks(void);
 int read_viminfo_filemark(vir_T *virp, int force);