extern int auth_xtextdecode(uschar *, uschar **);
extern uschar *b64encode(uschar *, int);
-extern int b64decode(uschar *, uschar **);
+extern int b64decode(const uschar *, uschar **);
extern int bdat_getc(unsigned);
extern uschar *bdat_getbuf(unsigned *);
extern int bdat_ungetc(int);
extern uschar *string_open_failed(int, const char *, ...) PRINTF_FUNCTION(2,3);
extern const uschar *string_printing2(const uschar *, BOOL);
extern uschar *string_split_message(uschar *);
+extern uschar *string_timesince(struct timeval *);
extern uschar *string_unprinting(uschar *);
#ifdef SUPPORT_I18N
extern uschar *string_address_utf8_to_alabel(const uschar *, uschar **);