patch 8.0.0548: saving the redo buffer only works one time

Problem:    Saving the redo buffer only works one time, resulting in the "."
            command not working well for a function call inside another
            function call. (Ingo Karkat)
Solution:   Save the redo buffer at every user function call. (closes #1619)
diff --git a/src/proto/getchar.pro b/src/proto/getchar.pro
index de33bfd..aac522f 100644
--- a/src/proto/getchar.pro
+++ b/src/proto/getchar.pro
@@ -8,8 +8,8 @@
 void flush_buffers(int flush_typeahead);
 void ResetRedobuff(void);
 void CancelRedo(void);
-void saveRedobuff(void);
-void restoreRedobuff(void);
+void saveRedobuff(save_redo_T *save_redo);
+void restoreRedobuff(save_redo_T *save_redo);
 void AppendToRedobuff(char_u *s);
 void AppendToRedobuffLit(char_u *str, int len);
 void AppendCharToRedobuff(int c);