Even more ANSIfication: fix as many function pointers and declarations as
possible.
diff --git a/Modules/parsermodule.c b/Modules/parsermodule.c
index b5414af..91ffef1 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -963,7 +963,7 @@
 /*  X (',' X) [',']
  */
 static int
-validate_repeating_list(node *tree, int ntype, int (*vfunc)(),
+validate_repeating_list(node *tree, int ntype, int (*vfunc)(node *),
                         const char *const name)
 {
     int nch = NCH(tree);