updated for version 7.3.720
Problem:    Proto files are outdated.
Solution:   Update the newly generated proto files.
diff --git a/src/proto/digraph.pro b/src/proto/digraph.pro
index be5be71..5573b8c 100644
--- a/src/proto/digraph.pro
+++ b/src/proto/digraph.pro
@@ -1,7 +1,7 @@
 /* digraph.c */
 int do_digraph __ARGS((int c));
 int get_digraph __ARGS((int cmdline));
-int getdigraph __ARGS((int char1, int char2, int meta));
+int getdigraph __ARGS((int char1, int char2, int meta_char));
 void putdigraph __ARGS((char_u *str));
 void listdigraphs __ARGS((void));
 char_u *keymap_init __ARGS((void));