About sysinit:
That would be part of the recompiled and refactored Delphi system unit. There is no version that works with FPC. We never refactored the FPC system unit.
What we did for FPC is made the complete Delphi RTL except the system unit FPC compatible at the compiler level: (basically the complete Delphi 7 RTL can be compiled with FPC.)
For KOL64 we have the essentials factored out to keep it small and fixed the Delphi Windows unit to work with FPC. The copyright for the Windows unit is Microsoft's, not Borland, and can be used freely.
As an aside: the refactored Delphi system units are compiled - or should be compiled! - with the GPL flag to not violate copyrights so that makes your application GPL'd too. Be aware of that. This is not the case for the windows units, these are free to use. Anyway rebuilding the Delphi system units is not for noobs.
[edit]
The other link is also 3.23, but seems to have some maintenance done. I did not check it any further, but from the header I can see that it includes my 64 bit patches so if they did not break anything during maintenance it should be OK for 64 bit. After my merges the whole code base became 64 bit compatible - at that point.
I am no longer actively involved in the core KOL development so I am not aware of the current status.