extern uschar *string_base62(unsigned long int);
extern uschar *string_cat(uschar *, int *, int *, const uschar *) WARN_UNUSED_RESULT;
extern uschar *string_catn(uschar *, int *, int *, const uschar *, int) WARN_UNUSED_RESULT;
extern uschar *string_base62(unsigned long int);
extern uschar *string_cat(uschar *, int *, int *, const uschar *) WARN_UNUSED_RESULT;
extern uschar *string_catn(uschar *, int *, int *, const uschar *, int) WARN_UNUSED_RESULT;