> I could understand that I can not build something form 1992 with todays > tools, but what I do not understand conceptionally, why the host compiler > seems to link with the target compiler's runtime, would it work as a > cross build then?
No, for a cross build you need an identical native compiler (same version) to start with. For native you need an older (or equal) compiler. > Could I even get into trouble building gcc4.9 with gcc-5 as host? Yes. Arno