meshtestproj.lpr(244,1) Error: Illegal COFF Magic while reading G:\n3d\repo\fpc-demos\precompiled\sdl.o
I think that this error is caused by wrong version/format of the sdl.o file. Therefore deleting it and compiling again should work.

Maybe the win and linux fpc linkers require different format of the *.o files. This would explain why it compiles only on linux. As for Delphi, if I remember correctly, it uses .dcu files, not .o so also no problem there.