+# define VALID_BACKUP_TYPE(Type) \
+ ((Type) == none \
+ || (Type) == simple \
+ || (Type) == numbered_existing \
+ || (Type) == numbered)
+
+extern char const *simple_backup_suffix;
+
+# ifndef PARAMS
+# if defined PROTOTYPES || (defined __STDC__ && __STDC__)
+# define PARAMS(Args) Args
+# else
+# define PARAMS(Args) ()
+# endif
+# endif
+
+char *find_backup_file_name PARAMS ((char const *, enum backup_type));
+enum backup_type get_version PARAMS ((char const *context, char const *arg));
+enum backup_type xget_version PARAMS ((char const *context, char const *arg));
+void addext PARAMS ((char *, char const *, int));