define startup stack in linker script, not assembly

Rsconscript

@@ -97,6 +97,7 @@ EOF
     env["LIBS"] += %w[gcc]
     env["OBJDUMP"] = "i686-elf-objdump"
     env.Program("^/hos.elf", glob("src/**/*.{S,c}"))
+    env.depends("#{env.build_root}/hos.elf", "src/link.ld")
     env.Disassemble("^/hos.elf.txt", "^/hos.elf")
     env.EfiImage("build/hos-efi.img", %w[^/hos.elf])
     env.BiosImage("build/hos-bios.img", %w[^/hos.elf])