Pointer to important manual page that should be written.

doc/crypto/err.pod

@@ -116,6 +116,8 @@ ERR_get_string_table(void) respectively.
 
 =head1 SEE ALSO
 
+L<CRYPTO_set_id_callback(3)|CRYPTO_set_id_callback(3)>,
+L<CRYPTO_set_locking_callback(3)|<CRYPTO_set_locking_callback(3)>,
 L<ERR_get_error(3)|ERR_get_error(3)>,
 L<ERR_GET_LIB(3)|ERR_GET_LIB(3)>,
 L<ERR_clear_error(3)|ERR_clear_error(3)>,