@Jose
The C-exec was supossed to be used in a future revision of AmigaOS und AT/Escom,
so using "the sources" for that was 100% o.k (if they did).
What use would it be for MOS ?
Exec : 0.0 as the exec-library in MOS works completly different due to not
being the kernel of the OS.
GFX/Layers/Intui ? That has been done by building a replycement out of CGX, I rather
doubt that old 68k-chipset-hacking sources were of any use here ;-)
DOS ? Well casting that trash away and replacing it with something sane was more
than needed anyways.
WB ? Amibient works different.
CLI(commands) lots of free replacements to be found on Aminet or in AROS.
Need I go on ?