./scfg.h:80:9: warning: 'SUB_HDRMOD' macro redefined [-Wmacro-redefined]

This is always going to call the terminal server's lprintf function (when used
with libsbbs.so/sbbs.dll) which is probably not what was intended.

Resolve reported clang warning:

inkey.cpp:592:20: warning: implicit conversion from 'long' to 'int' changes value from 2147483648 to -2147483648 [-Wconstant-conversion]
         if(!term_supports(MOUSE))
             ~~~~~~~~~~~~~ ^~~~~
 ./sbbsdefs.h:574:19: note: expanded from macro 'MOUSE'
 #define MOUSE           (1L<<31)                /* Mouse supported terminal                             */

This is hacky cruft here. We shouldn't have the declaration in multiple
places. It probably shouldn't be in sbbs.h.

load_cfg() calls free_cfg() before do_cryptInit() is called, so the ssl_rwlock
was uninitialized here.

Holding the lock around session establishment should not be needed,
but we need to protect tls_certificate read and usage.  Since we
don't have rwlocks in xpdev (yet?), hack together a crappy rwlock
that does what we need.

Also, remove "CONSECUTIVE", which doesn't really make sense when the number
of login attempts in 1.

There's a hidden checkbox on the CodeInputForm now (explaining why the edit/
combo box is now moved up).

Renamed the "Perm Filter Threshold" to "Auto Filter Threshold".

Changed help text from "Permanent" to "Persistent"

More readable/friendly log messages and ip.can reason strings

The number of failed login attempts. It's something.

Update wording and add more help text.

Now a sysop can "perm block" a client (IP address) for a limited amount of
time rather than always forever.

Add more displays of the ip.can details when actively blocking a client.

Moved twit/trash functions from userdat.c to trash.c

For symmetry

I wanted a couple of features for filters (e.g. blocked IP addreses):
- expiration date, optionally (only block for a limited time)
- display details of reason for filter in log messages (at time of block)

I've been thinking for some time that these files should be converted to .ini,
but then it occurred to me that I could do a sort of hybrid where the metadata
was key/value pairs tab-delimited from the search-pattern (first text on the
line). This is backward comaptible, relatively easy to view/edit by hand, and
extensible (easy to add/remove metadata fields in the future). So they'll
remain as text/*.can files.

The maximum line length for findstr/trashcan parsed files extended from 255 to
1000 characters.

Moved all trashcan-related functions from scfglib1.c to (new file) trash.c.

For the first time, I actually tested a build on WSL *before* committing to
Git. So, this *should* pass CI the first time. :-O

So move to nopen.h

Move the nopen-specific constants from sbbsdefs.h to nopen.c

This helps svdmodem to use findstr->nopen without more sbbs/smblib deps

... especially around incoming connection acceptance, blocked-IPs/hostnames

Many searches are done (e.g. in the mail server, QWK import) for either of 2
strings in single file or list, so let's optimize that to a single iteration
through the file/list. This should reduce some redundant file I/O.

I do find this API a little confusing with the filename or list at the end
of the argument list, but kept it consistent with the existing single string
findstr functions (which are now just wrappers for the new 2-string flavors).

I noticed during this update that findstr() did not share the same behavior
as findstr_in_list() (feature added in commit f08f2137) whereby if all the
patterns were negative searches (beginning with '!'), then *all* the
negative matches would have to be successful (not just the first) for the
function to return true. So now findstr() behaves like findstr_in_list()
in this regard.

I also added some optimizations to findstr_in_string().