patch 7.4.730 Problem: When setting the crypt key and using a swap file, text may be encrypted twice or unencrypted text remains in the swap file. (Issue 369) Solution: Call ml_preserve() before re-encrypting. Set correct index for next pointer block.

/* pty.c */
int OpenPTY __ARGS((char **ttyn));
int SetupSlavePTY __ARGS((int fd));