As requested by Nelgin.

And this option is mutually exclusive with the [dir-code] parameter.

... from ERROR to WARNING, so the repeats won't be logged to error.log file
and won't (normally) be sent as notifications (e.g. emails) to the sysop. The
duplicates are identified as from the same source file and line number as the
immediately previous logged error within the last 12 hours. String comparison
doesn't really work for deduplication since if you look closely, the errors
usually are *not* exact duplicates (i.e. there's a node number or a socket
descriptor or something that uniquely identifies the user/client/session).
Repeated errors don't increment the node's error counter either.

This does not de-duplicate errors logged via other means (e.g. direct calls to
log()/lputs(),lprintf() with a severity of LOG_ERR or higher), but will
solve the majority of duplicate errors that can be logged from the terminal
server.

So this at least partially addresses issue #619.

Next step is to implement a KEX.

With this, SyncTERM and SexPOTS on *nix won't actually need to strip
received bytes themselves.  No idea what Windows does though, so
it'll likely still be needed forever.

DDMsgReader: New user option & behavior: In a message list, when selecting/toggling a message, it can now optionally move the cursor to the next message

See merge request !479

DDMsgReader: New user option & behavior: In a message list, when selecting/toggling a message, it can now optionally move the cursor to the next message

This happened to work before commit d49134e6 since iniReadFile()
didn't return false upon any read error, so File.iniSetAllObjects() didn't
realize that the read of (any) existing file contents had failed (because the
file was open write-only).

This explains why the *.avatars.ini files were pretty much blank as of late
and no networked message posters were having their avatars displayed.
Reported by Codefenix (thank you).

Add a print/log line to tell us how many avatars were parsed, just for extra
traceability of this script and any potential failure cause.

The plan is to hide non-standard stuff in here.  Currently, just
has [[maybe-unused]] from C23.

The intent is that this will be a library implementation of SSH
which allows simple extension of the base protocol, and exposes all
defined features of the protocol (including ones nobody uses).

This will support both client and server, with initial focus on the
client implementation for use in SyncTERM.

The goal of the core library is to only support the most secure
standard methods.  When there are multiple methods that are not
clearly of differing levels of security, the most common two will
be implemented (ie: RSA and Ed25519).

Additionally, care will be taken during development to allow for
the OpenSSH Encrypt-then-MAC MAC modes in the expectation that
someone will standardize an ETM mode at some point, and I expect
to write an extension to support it soon after DeuceSSH is
complete.

Finally, if I cannot mitigate Terrapin without non-standard
extensions, the OpenSSH "strict KEX" extension will be supported
until there's a standard defined that solves the issue.

Even though we use O_EXCL, networked file systems still sometimes allow the
secondary open() to succeed. We use record locking in xpdev's sopen()
implementation for *nix, so this lock will insure such opens (and locks) will
now fail.

This is an attempt to address occassional error on Vertrauen:
ERROR 2 (No such file or directory) renaming *.rep to *.bad

Return correct error value upon seek failure.

When OFD locks are available, that's what we should be using.
Otherwise, we suffer the horrible behavior of POSIX file/region locks and
a subsequent open/close of the file releases any/all locks on it.

This is currently in an !BSD block, which appears to include macOS, but
macOS *does* support OFD locks, so I'll be fixing that here shortly.

"performing custom action"

Normally, the sysop would set the NodeActionCustom text.dat string
to override this.

This is to be used (e.g. instead of NODE_BXFR) for sysop-custom node actions.

so that if multiple entities call these functions at the same time, they
don't retry at exactly the same times.

Add/use SOCKET_STRERROR which gets the description of the *last* socket
error.

We should start using socket_errno(true) in place of ERROR_VALUE (horribly
named macro) for comparing last socket error nubers against values/macros
from errno.h.

Eliminate get_socket_errno(), unused and redundant with socket_errno().

Really need to make the option order (arity) neutral

Addresses Clang warnings about deprecation

This fixes all the "argument unused during compliation" warnings

This breaks armv7 FreeBSD builds.  Presumably it breaks anything
else where va_list isn't a pointer too... and there's no real reason
to expect a va_list to be a pointer except "it's a pointer on the
platform I looked at".

These functions now return a common set of non-zero error values (where
appropriate), defined in userdat.h

Don't return errno.

getnodedat() now performs a non-locked read by default.

Perform more checks of getnodedat() return value before calling putnodedat()
to avoid unintentionally zeroing out node.dab records.

Add/use unlocknodedat() method for unlocking a node.dab record without
writing.

Note: The userdat.c getnodedat() and putnodedat() still return int (i.e. 0 on
success), so that can be confusing.

Since this script already sets an on_exit() handler to call uifc.bail()
it doesn't have to call it again (technically, before) in the "Done" block.
This results in "UIFC is unitialized" error displayed, as reported by
Fernando Toledo. Fixing issue #830

Set WIN_ESC (remains active, but greyed when ESC key pressed) mode flag
on main menu while we're here. That looks better.