Split of architecture-dependent and -independent functions for i386,

mainly in the kernel and headers. This split based on work by
Ingmar Alting <iaalting@cs.vu.nl> done for his Minix PowerPC architecture
port.

 . kernel does not program the interrupt controller directly, do any
   other architecture-dependent operations, or contain assembly any more,
   but uses architecture-dependent functions in arch/$(ARCH)/.
 . architecture-dependent constants and types defined in arch/$(ARCH)/include.
 . <ibm/portio.h> moved to <minix/portio.h>, as they have become, for now,
   architecture-independent functions.
 . int86, sdevio, readbios, and iopenable are now i386-specific kernel calls
   and live in arch/i386/do_* now.
 . i386 arch now supports even less 86 code; e.g. mpx86.s and klib86.s have
   gone, and 'machine.protected' is gone (and always taken to be 1 in i386).
   If 86 support is to return, it should be a new architecture.
 . prototypes for the architecture-dependent functions defined in
   kernel/arch/$(ARCH)/*.c but used in kernel/ are in kernel/proto.h
 . /etc/make.conf included in makefiles and shell scripts that need to
   know the building architecture; it defines ARCH=<arch>, currently only
   i386.
 . some basic per-architecture build support outside of the kernel (lib)
 . in clock.c, only dequeue a process if it was ready
 . fixes for new include files

files deleted:
 . mpx/klib.s - only for choosing between mpx/klib86 and -386
 . klib86.s - only for 86

i386-specific files files moved (or arch-dependent stuff moved) to arch/i386/:
 . mpx386.s (entry point)
 . klib386.s
 . sconst.h
 . exception.c
 . protect.c
 . protect.h
 . i8269.c

kernel/Makefile

@@ -1,51 +1,57 @@
 # Makefile for kernel
 
+include /etc/make.conf
+
 # Directories
 u = /usr
 i = $u/include
 l = $u/lib
 s = system
+a = arch/$(ARCH)
 
 # Programs, flags, etc.
 CC =	exec cc
 CPP =	$l/cpp
 LD =	$(CC) -.o
-CFLAGS = -I$i $(CPROFILE)
-LDFLAGS = -i 
+CPPFLAGS=-I$i -I$a/include
+CFLAGS=$(CPROFILE) $(CPPFLAGS)
+LDFLAGS=-i 
 
-HEAD =	mpx.o
-OBJS =	start.o protect.o klib.o table.o kprintf.o main.o proc.o \
-	i8259.o exception.o system.o clock.o utility.o debug.o profile.o
+# first-stage, arch-dependent startup code
+HEAD =	head.o
+FULLHEAD = $a/$(HEAD)
+
+OBJS =	start.o table.o main.o proc.o \
+	system.o clock.o utility.o debug.o profile.o interrupt.o
 SYSTEM = system.a
+ARCHLIB = $a/$(ARCH).a
 LIBS = -ltimers -lsysutil
 
-
 # What to make.
 all: build 
 kernel build install: $(HEAD) $(OBJS) 
-	cd system && $(MAKE) -$(MAKEFLAGS) $@
-	$(LD) $(CFLAGS) $(LDFLAGS) -o kernel \
-	$(HEAD) $(OBJS) \
-	$(SYSTEM) $(LIBS)
+	cd system && $(MAKE) $@
+	cd $a && $(MAKE) $@
+	$(LD) $(CFLAGS) $(LDFLAGS) -o kernel $(FULLHEAD) $(OBJS) \
+		$(SYSTEM) $(ARCHLIB) $(LIBS)
 	install -S 0 kernel
 
 clean:
 	cd system && $(MAKE) -$(MAKEFLAGS) $@
+	cd $a && $(MAKE) -$(MAKEFLAGS) $@
 	rm -f *.a *.o *~ *.bak kernel
 
 depend: 
 	cd system && $(MAKE) -$(MAKEFLAGS) $@
-	/usr/bin/mkdep "$(CC) -E $(CPPFLAGS)" *.c *.s > .depend
+	cd $a && $(MAKE) $@
+	/usr/bin/mkdep "$(CC) -E $(CPPFLAGS)" *.c > .depend
 
 # How to build it
-.s.o:
-	$(CC) $(CFLAGS) -c -o $@ $<
-
 .c.o:
 	$(CC) $(CFLAGS) -c -o $@ $<
 
-# Include generated dependencies.
-klib.o:	klib386.s klib88.s
-mpx.o:	mpx386.s mpx88.s
-include .depend
+$(HEAD): 
+	cd $a && make HEAD=$(HEAD) $(HEAD)
 
+# Include generated dependencies.
+include .depend