fix image generation

extra/Makefile

@@ -1,4 +1,5 @@
 OBJCOPY=objcopy
+ASFLAGS+=-m32
 
 all: sos_qemu.img
 
@@ -30,7 +31,7 @@ sos.bin: sos_bsect.elf
 # linked together (hence we deal with a SINGLE image that we split
 # above) because they share some symbol definitions
 sos_bsect.elf: bootsect.o compile_kernel
-	$(LD) --warn-common -T ./sos_bsect.lds -o $@ \
+	$(LD) -m elf_i386 --warn-common -T ./sos_bsect.lds -o $@ \
 		bootsect.o $(wildcard ../hwcore/*.o ../drivers/*.o ../sos/*.o)
 
 compile_kernel: