New function (derived from sbbs_t::utf8_to_cp437()): unicode_to_cp437()
New utf8 functions: utf8_replace_chars(), utf8_str_is_valid().
utf8_getc() enhancement: val arg may be NULL (for length/validation uses).

heavy-handed (performs strdup/malloc's and modifications of the strings),
so a temporary hack is to perform a case-sensitive search (using the standard
strstr() function) first. The results won't exactly match the traditional
strstr() and the performance improvement is only for positive matches
(where the correct case was guessed in the passed 'needle' string arg).
TODO: re-write or copy a good/fast strcasestr() implementation for Win32 builds.

Fix age-old bug with Borland/C++Builder built executables (Windows):
to achieve compatibility with  the default __cdecl symbol naming rules of
Visual C++, we were using __stdcall convention for DLL functions when
building code with Borland/C++Builder tools and using the default (__cdecl)
convention when building with Microsoft (Visual C++) tools. Although this
allowed symbols to be located when linking, the calling convention mismatch
caused a stack cleanup issue that very rarely manifested itself in a bug
(e.g. exception of some kind in sbbsctrl.exe, usually). Mismatching
the calling conventions was unintentional (I thought the default for MSVC
DLL functions was __stdcall) - but since the calls to MSVC-Built DLL functions
worked 99% of the time, I didn't realize there was an underlying issue. So I
now work-around the DLL symbol naming mismatch using a command-line option (-a)
passed to implib in src/sbbs3/ctrl/makelibs.bat

I had previously worked-around exceptions when calling MSVC DLL functions in
sbbsctrl.exe by calling the problematic DLL functions from a timer tick handler
rather than a user control (e.g. button) event handler. Those work-arounds can
now be removed.

The erroneous "DLLCALL" definition design pattern was replicated (copy/pasted)
to many other projects' header files in cvs.synchro.net. In the future, we may
want to just remove all instances of *CALL since they now serve no purpose and
appear as useless "Kruft" (but do allow us to more-easily globally change DLL
function calling conventions if/when necessary in the future).

error: 'PTHREAD_MUTEX_RECURSIVE_NP' undeclared
as ported by GeoKM

If the modify callback function returned a pointer *within* the list item's
allocated buffer, the strcpy() would copy from potentialy free'd memory as
realloc may change the location of the heap buffer when resizing.
Fixed by allocating a copy of the returned pointer before freeing the original
list item buffer and then just assign the allocated pointer (no copying
needed). This likely will result in more heap fragmentation for modified list
items are now newly-allocated buffers rather than reallocated existing buffers
but the other option would have been to allocate a temporary copy of the string
before reallocating and then copying and that would've been a lot more overhead
than with this approach.

This likely fixes any crashes seen in recent revs of v3.17c (e.g. when
imported QWK or REP packets and text/*.can and the twitlist.cfg are parsed).
The sighting on Vertrauen was only in the Windows build and appeared when
importing QWK/REP packets.

commit.

a caller-supplied function (callback) which can modify each string or leave
the string in tact by returning NULL. Shrinking strings is trivial while
expanding strings (making them bigger) is a little more involved, probably
using the cbdata to pass a temporary buffer around to store each expanded
string or returning a new globally-valid pointer.
Removed the malloc.h #include as we haven't used alloca() here for a while.

HEX_DIGITS() and DEC_DIGITS()

same name in uifc/filepick.c - specifically with regards to paths that
begin with a / (or \ on Windows).

pathname (directories must end in a '/'). Unlike getfname() which returns an
empty string if passed a path ending in a '/'.
Useful with glob(.., GLOB_MARK).

There's no reason to call access() before stat() since stat() will fail
(return -1) if the file does not exist.

now have their output translated to PETSCII equivalents for PETSCII terminals
(but input is not yet translated).
.seq files are now sent untranslated via printfile() and putmsg() to PETSCII
terminals (using the new P_PETSCII putmsg mode flag).
.seq files (and P_PETSCII mode text printed via putmsg) is now converted
(poorly) from PETSCII to CP437 - this is still a work-in-progress.
Remove the remants of WIP and HTMLterm support from putmsg() and printfile().

So Omegix recently asked in the Synchronet Discussion group whether or not
a PETSCII (Commodore) terminal could be used to access his Synchronet BBS.
Now, the answer is "Yes". :-)
The major issues addressed:

- detecting a PETSCII terminal, solved by assigning specific (configurable):
  TCP ports to be used for incoming PETSCII connections, by default:
  port 64 is for 40-column PETSCII and port 128 is for 80-column PETSCII,
  but if the terminal sends a Telnet Window Size reply (e.g. SyncTERM), then
  either size terminal should fine on either port.
  The port numbers are configurable in the [BBS] section of your sbbs.ini
  file using the new keys: PET40Port (default value: 64) and PET80Port
  (default value: 128). Having these keys set doesn't make make the terminal
  server listen on that additional port - you'll need to add more
  IP:port combinations to one of Interfaces values, example:
    TelnetInterface=71.95.196.34,71.95.196.34:64,71.95.196.34:128
  And you don't have to use Telnet for the PETSCII connections - you could use
  RLogin or SSH instead (or in addition).

- support for terminal widths < 80 columns:
  This was achieved through a combination of text.dat changes (numerous),
  new Ctrl-A and @-codes and new optional terminal-width-specific menu files
  (e.g. text/menu/main.40col.asc)
  A side effect of these changes is actually better support for terminals
  *wider* than 80 columns as well!

- support for terminals that don't expand tabs to spaces (e.g. PETSCII):
  The terminal server now handles tab expansion with a run-time settable
  tab-size (default size: 8)

- conditional access based on PETSCII (or small) terminal use (or not):
  + New PETSCII ARS keyword (boolean)
  + New COLS and ROWS ARS keywords (for terminal width and height requirements)
  + New TERM (string) ARS keyword

New @-codes:
  - WORDWRAP, when placed at the top of a file, enables auto-wordwrap for
              lines longer than the terminal width
  - CENTER, the text following before an end of line will be displayed centered
            on the terminal (whatever the width, in columns)
  - CLEAR, like CLS, except it ignores (doesn't display) a CRLF that follows
  - COLS, current number of terminal columns (width)
  - ROWS, current number of terminal rows (height)
  - TERM, the auto-detected or reported terminal type (e.g. ANSI, TTY, etc.)
  - SYSONLY, toggles "echo" (display) off/back-on for non-sysops
            similar to the Ctrl-A( and ) codes, but more convenient to use
            (and PabloDraw won't strip the @-code from the file like it does
             with Ctrl-A codes it doesn't support)

New Ctrl-A codes:
  - \ conditional new-line/continuation when the terminal width is < 80 cols
      prints the new text.dat string LongLineContinuationPrefix

yesno() will now return true if passed a blank string.
noyes() will now return false if passed a blank string.
getstr()'s input length limiting based on terminal width is more broadly
           applied now (not just when using the K_LINE mode flag).

New JS bbs object method: menu_exists(<base_filename>) returns Boolean
New JS console object property: tabstop (Number)
New JS console object methods: getbyte() and putbyte() to recv/send raw byte
    value with (very little) interpretation/intervention by the terminal server
New JS console object method: creturn() - performs a carriage return
    (or equivalent)
New JS (and C) printfile() mode flag: P_TRUNCATE, causes long lines to be
    truncated, rather than displaying causing a line-wrap.

New text.dat strings:
  - NoAccessTerminal (for ARS check failures)
  - LongLineContinuationPrefix (for breaking long lines for 40col terminals)
  - Scanning (replaces a previously hard-coded "Scanning" string)
  - Done (replaces a previusly hard-coded "Done")
  - Scanned  (when finished scannning, clears the progress bar)

of default style elements.

and no actual observed problem.

malloc'd strings.

elements (member variables) would be changed to point to a string constant.
Don't do that - instead just use local stack variables for those style
element default values. This leads the way to constifying the style arguments
in the future and allows the caller to use non-NULL style elements as indicator
of something that should be freed if the caller allocated some memory for it.

section) in the returned stringlist.
Created iniAppendSectionWithKeys(): similar to iniAppendSection, but a list
of list of "key=[value]" strings (like those returned from iniGetSection())
can be added at the same time.

a faliure.
delfiles() now returns a negative result upon any deletion errors.

Most of the copyright years in the source code were misleading (the date of
most recent publish was actually later) and all were unnecessary. I've been
removing copyright years piecemeal, for a long time, but I decided it was time
to just perform a bulk search and (mostly) replace. In some cases, I left
old copyright years on files that either are not used (and soon to be removed)
or obsolete and unlikely to ever be touched again (e.g. Win9x FOSSIL VXD). Some
of the runtime binaries still contain copyright years and those were updated to
2018.

the number of decimal places in the resulting string.

Created byte_estimate_to_str(), much like byte_count_to_str(), except the
byte count is rounded to the nearest tera/giga/mega/kilo-byte
(technically tebi/gibi/mebi/kibi-byte, but ugh, I'm old-sk00l!).

instead truncate to the new length after writing the contents. This should
make .ini files more tolerate of "out of disk space" situations and reduce
the risk of lost data (0-byte .ini files) due to low/no disk space.

cast from pointer to integer of different size

(e.g. "Zones=1,2,3,4,5,6").

literals (e.g. won't detect and escape them automatically). If you set
a key value with carriage-returns and line-feeds, those will end up in the
.ini file as-is, so use with caution.