Remove dependency on `scio.h` and `sctchar.h` from C compiler source.

Remove dependency on `scio.h` and `sctchar.h` from C compiler source.

---

So, everything works now!
No, it's a joke. )))
Optlink is surely propected from being compiled by `dmc`'s ICE:
```
dmc -c newlibc -NTPASS1_TEXT -I..\common -r -N_ -o -o.\OBJNT\newlibc.obj
Internal error: cgcod.c 750
```