temp directory (system.temp_dir in JS), sbbs will read in this file and append
it to the message body *after* the user's .sig file (if there is one).
Bug-fix: don't append .sig files when editing extended file descriptions.

time (e.g. "00:00:00"). Synchronet v3 has always forced this value to 0 since
it's inaccurate over TCP/IP with the current hard-coded "CPS" rate of 3000
(i.e. bytes-per-second).

fit on the current line.

when posting.

for HEAD requests.

Content-Length header for static files.

'subnum' as the first command-line argument.
Also, set the current sub-board value used for ARS comparisons before passing
control to a Scan Msgs mod (if there is one), just in case the mod uses ARS
(e.g. bbs.compare_ars) to check for access.

Display the "No messages found" text when attempting to thread up or down
and there is no corresponding message.

for sbbs_t::loadposts().

Removed extra smb_freemsgmem() stuff in listmsgs() loop (leftover?).

scanposts(), and listsub(). These functions are exposed in the JS 'bbs' object
as scan_subs(), scan_msgs(), and list_msgs().
Wherease previously, all of "your messages" (messages addressed to you)
would be found/displayed if the user answered (Y)es to the "Subjects Only?"
prompt, and only un-read message (to you) would be displayed if they answered
(N)o to the "Subjects Only?", providing long-standing confusion about the
different behavior, now the user is prompted whether to display un-read
messages only (in scansubs/scanallsubs), and in the case of the logon
question to "Search all subs for un-read messages to you?", only un-read
messages are listed/displayed, regardless of how the user answers the
"Subjects Only?" question.
SCAN_UNREAD is only applicable when combined with SCAN_TOYOU.

Added new commands to the msg reading prompt: 'N' (list new messages), 'U'
list un-read messages to-you.

2 new text.dat entries: DisplayUnreadMessagesOnlyQ and NoMessagesFound

getusrsub() returned the completely wrong sub-board number. It assumed that
getusrgrp() returned a 0-based index when in fact it returns a 1-based group
number. This bug was only visible when using certain @-codes (e.g. "SN",
"SL", "SR", and "SMB_SUB_NUM") when a sub-board was open via Synchronet
internal function (i.e. not via JS MsgBase class). If the current group was the
last group visible to the user, this would cause a crash.

JS model (bbs.scan_msgs() method).

was never used. This was intended to be a method for internationalization,
letting the sysop change which key is used as the uiniversal "quit" key.
This commit replaces most of the uses of the hard-coded 'Q' for quit wtih the
3rd charcter in the text.dat YNQP string. Some hard-coded menus still have the
'Q' key hard-coded and will need to be addressed later. The text.h YN index
macro was changed to YNQP and the JS text index variable name will change
as well.

draw the top line and first left vertical row in a file list box.  The rest
of the box was drawn in whatever attribute text.dat left it in.

Optionally, external modules may be executed in place of "built-in" operations
for:
- reading mail (email or netmail)
- scanning posts (searching/scanning/reading a single sub-board)
- scanning sub-boards (all, one, or a group)

Each of these may be configured (in SCFG->System->Loadable Modules)
with command-line options for a total length of up to 63 characters.

Note to module programmers: each module here will be passed additional
command-line arguments to indicate how or why the user operation was invoked.

For the Reading Mail module, the 'which' value (in decimal) and the user-number
is passed (in decimal). Usually the user-number will be the current user logged
in, but not always (e.g. if the user is a sysop and reading other user's mail).
The 'which' values (defined in load/sbbsdefs.js) of MAIL_YOUR, MAIL_SENT,
and MAIL_ALL must be handled (MAIL_ANY won't be used).

For the Scan Posts module, the sub-board number and scan mode (both in decimal)
and the 'find' string (text being searched for) are passed as arguments
(in that order). The scan mode values (defined in sbbsdefs.js) are the same as
those supported by bbs.scan_posts(). All of the values should be supported
and they can be combined (e.g. SCAN_CONST|SCAN_NEW
and SCAN_NEW|SCAN_TOYOU). The 'find' string is only used if the SCAN_FIND mode
bit is set. It is the responsibilty of the module (if configured) to enforce
sub-board read access restrictions.

For the Scan Subs module, the first argument is 1 if "all subs" are being
scanned, 0 otherwise (normally the user is prompted for the breadth of the
scan in this case, but that's up to the module author), and the scan 'mode' is
passed in decimal, in that order. If the SCAN_FIND mode flag is passed in, this
module should prompt the user for the text string to search for. If this module
is not configured, the Scan Posts module will be executed for each sub-board
scanned.

Recursion protection was added, so it is actually possible for the Read Mail
module, for example, to call bbs.read_mail() and it'll work, but why would you?

If any of these user operations are initiated during logon, at the request of
Baja or JavaScript module, or whatever, and if the module is actually
configured (and not already executing to handle the operation), the module
will be executed in-place-of the built-in functionality. Feedback welcome,

by access_d.  Broken since v1.18 on Feb. 10th,  2015.

ID is a pointer on at least FreeBSD, cast to uintmax_t instead of DWORD.

scripts global scope (as opposed to js.global which is the instance global
scope), and having exit() define exit_code in js.scope instead of js.global.

This also sets exit_code in js.scope to null when preparing to execute a new
script.  If a new script starts in the same scope as an old one, the old
exit_code value will be destroyed.

This should only impact scripts where js.global != js.scope (bbs.exec()ed,
and mailsrvr)

(or by adding NOCIRCULARFWD to your sbbsecho.cfg):
When "Circular Path Detection" is enabled (the default), the old behavior was
to still forward the message to any links (if there are any), but not import
the circular/looped message (likely a dupe). Now, if you set this new option
to no (or add "NOCIRCULARFWD" to your sbbsecho.cfg), the message will be
completely ignored and not fowarded to any links (if there are any).
If you have no downlinks or you have circular path detection disabled, this
new option does nothing. The default is the old behavior (forward circular
messages).
Also updated the Toggle Options help text in echocfg (many options weren't
documented.

this read() call will block indefinitely. Fall-through to pseudo-random seeding
if read() fails. Fix for FozzTexx-reported problem on reddit.

hash entries will then have incorrect or invalid message numbers.

your return value anyway.

item enqueing stuff which has been carefully preserved and equally carefully
never used.