As gcc can compile hellow.c on an ARM 6, I supped yesterday and got
the following while building a kernel:

cc  -O2 -Werror -Wall -I. -I../../../../arch -I../../../.. -nostdinc
  -DMACHINE_NONCONTIG -DCPU_ARM6 -DIOMD -DRISCPC -DARMFPE -DFIFO -DINET
  -DPFIL_HOOKS -DCOMPAT_43 -DCOMPAT_13 -DCOMPAT_12 -DSYSVMSG -DSYSVSEM
  -DSYSVSHM -DSHMMAXPGS="0x400" -DKTRACE -DIRQSTATS -DMOUSE_IOC_ACK
  -DDIAGNOSTIC -DPOSTMORTEM -DDDB -DIPFILTER -DIPFILTER_LOG
  -DMAXUSERS=32 -D_KERNEL  -Darm32 -Wcomment  -c
  ../../../../arch/arm32/arm32/process_machdep.c
In file included from
  ../../../../arch/arm32/arm32/process_machdep.c:77:
machine/cpus.h:148: field `sc_device' has incomplete type
*** Error code 1



Note that machine/cpus.h is only included if ARMFPE is defined (as is
the case for me). Same error occured before and after a make includes.

# ls -l /usr/include/machine/cpus.h
-r--r--r--  1 root  wheel  4754 Oct 14  1997 /usr/include/machine/cpus.h

machine/cpus.h:

#ifndef _LOCORE
#include <sys/param.h>  <-- doesn't include a definition of struct device
#endif

struct cpu_softc {
        struct  device sc_device;
        int     sc_open; 
};    

sys/param.h:

#ifndef _LOCORE
#include <sys/types.h>
#endif
#include <sys/syslimits.h>
#ifdef _KERNEL
#include <sys/cdefs.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/ucred.h>
#include <sys/uio.h>
#endif
#include <sys/signal.h>
#include <machine/param.h>
#include <machine/limits.h>

etc. and none of them include sys/device.h, so should
#include <sys/device.h> be added to machine/cpus.h ?

Cheers,

Patrick