instead of USER_RECORD_LINE_LEN

and then unlocking again. So... make readuserdat() optionally leave the
record locked, reducing a lot of unnecessary lock/unlocking in here.

Move the user field index definitions to userfields.h

Also resolved some 32 vs 64-bit 'long' issues/ambiguities that have long-remained. :-)

This commit also removes logon.lst file support.

There's a TODO block remaining in js_user.c for setting portions of a user's birthdate (e.g. just the year or month or day).

Don't use cnflib.js any longer, now obsolete

Untested, but matches implementation from https://github.com/veeso/termiWin/blob/master/src/termiWin.c

and declare function in comio.h

Rather than only matching exact zone numbers as a final "nearest" address
search, use a "nearest zone" matching algorithm ("nearest" being the most
mathematically near). This way, replying to netmail from a zone 2 address
would always match a zone 1 source address, regardless of how many othernet
addresses are configured and which order they are configured in SCFG.

Fixes issue #447 reported by Charles Blackburn (FBOBBS)

We no longer use/require the USE_DOSEMU definition anywhere else, so
this was just a miss when the DOSEMU patch was perm-enabled.

sbbs3/../xpdev/netwrap.h:45:27: warning: 'parseIPv6Address' has C-linkage specified, but returns incomplete type 'struct in6_addr' which could be incompatible with C [-Wreturn-type-c-linkage]
DLLEXPORT struct in6_addr parseIPv6Address(const char*);
                          ^

New Medium impact and a low impact issue still needs to be triaged.