always prefer fatal error messages rather than temp error messages

avoid syserr on final 221 message; this can occur if the other end
closes prematurely

add debugging to putoutmsg

fix null pointer reference in syslog message

fix bogus error message with open timeout in :include: -- this also
fixes a bug that caused resolver errnos to conflict with real errnos

old 4.3BSD changes

allow 6xx codes to mean "warnings sent to postmaster"

clean up error handling, including concept of local error handling

huge number of changes for 8.2, including IRIX & Solaris portability;
improved error checking; fix -m flag and add -O flag in maps; fix long
DNS timeouts; relax safefile restrictions; add -X command

huge number of changes for 8.2, including IRIX & Solaris portability;
improved error checking; fix -m flag and add -O flag in maps; fix long
DNS timeouts; relax safefile restrictions; add -X command line flag; etc.

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4.4BSD snapshot (revision 8.1); add 1993 to copyright

try to improve closed connection error handling

don't go into recursive syserr loop if error printing syserr

avoid writing an error message announcing that you can't write the
message

pessimize on channel flushing

type conflicts

first cut at merged map/alias implementation

fix some bogus messages being printed in mailq command

improve error logging on OutChannel I/O errors

clean up error message printing, especially for deferred messages

fix comment on message()

Extended Load Average (XLA) hooks

check for I/O errors on OutChannel

portability

fix problem with prototype mismatches

add X-Authentication-Warning: headers on possible attempts at forgery