I ran into this - rebuilding a Delphi 4 project this week.

dcc32.exe b "any.dpr"

Instead of DCC32.CFG, I had to create a "ANY.CFG" - include /UC:\Delphi4\Lib - and my system.pas is missing problems went away. [Normally I code in D7, it too had the same issue, /UC:\Delphi7\Lib resolved it in a .cfg named the same as the .dpr file.