always disassemble kernel when building

Rsconscript

@@ -65,7 +65,9 @@ EOF
     env["CCFLAGS"] += %w[-ffreestanding -Wall -O2]
     env["LDFLAGS"] += %w[-ffreestanding -nostdlib -T src/link.ld]
     env["LIBS"] += %w[gcc]
+    env["OBJDUMP"] = "i686-elf-objdump"
     env.Program("^/hos.elf", glob("src/**/*.{S,c}"))
+    env.Disassemble("^/hos.elf.txt", "^/hos.elf")
     env.Image("build/hos.img", %w[^/hos.elf])
   end
 end