Added pop3_save_uidl setting. When UIDLs are sent to client, save them to dovecot-uidlist. This allows changing pop3_uidl_format without messages getting re-downloaded. It's also useful with virtual POP3 INBOX when UIDLs are based on IMAP UIDs that may not be as stable as in non-virtual INBOX.

#ifndef DUP2_ARRAY_H
#define DUP2_ARRAY_H

struct dup2 {
	int fd_src, fd_dest;
};
ARRAY_DEFINE_TYPE(dup2, struct dup2);

void dup2_append(ARRAY_TYPE(dup2) *dups, int fd_src, int fd_dest);

int dup2_array(ARRAY_TYPE(dup2) *dups);

#endif