Ok, now am confused. I just ran the installers in this order:
1) The setup that unpacks another setup for lazarus, and some delphi ides.
2) Ran the setup for lazarus. Instead of default location, I use my own path as always, c:\dev\comp\tms\2020 (since I have ...\2004 iw installed too).
3) Ran the tms subscription manager and with it installed all the fnc packages under the indicated path. Also ran the delphi installers without actually installing on any IDE.
4) installed lazarus, and inside lazarus the following,
5) installed webcore package. It had the problem that started this thread and was fixed with your advise.
6) try to install fncwebcore but it failed, so, installed all the remaining FNC components.
7) now am trying to install the last package in mention, tmsfnccorewebcorepkg.lpk, which is under c:\dev\comp\tms\2020\TMS FNC Core. And yes, there is a bunch of delphi related files there, as well as number of inc files. There is only one WEBLib.TMSFNCDefines.inc and it contains exactly what you wrote above.
I actually repeated the whole procedure, including uninstalling lazarus,wiping every folder and start over, with the purpose of cleanly changing lazarus version.
As far as I know, I didn't make any change to paths, so don't have any idea of how I ended up with the wrong inc file, or how the existing file references the wrong set. The source code only was changed under your advise.
Where should I look now?