There is no arch/i386/firmware/linuxbios directory

src/arch/i386/Makefile

 # i386-specific directories containing source files
 #
 SRCDIRS		+= arch/i386/core arch/i386/transitions arch/i386/prefix
-SRCDIRS		+= arch/i386/firmware/pcbios arch/i386/firmware/linuxbios
+SRCDIRS		+= arch/i386/firmware/pcbios
 SRCDIRS		+= arch/i386/image
 SRCDIRS		+= arch/i386/drivers/bus
 SRCDIRS		+= arch/i386/drivers/net