message: add rules to split debug symbols from binary
diff: @@ -21,6 +21,8 @@ endif
  default:
  @RUSTFLAGS="-L ../target/$(target)-kernel/$(rdir)" cargo build $(opt) --target $(target)
  + @$(arch)-hermit-objcopy --only-keep-debug target/$(arch)-unknown-hermit/$(rdir)/hctests target/$(arch)-unknown-hermit/$(rdir)/hctests.sym
  + @$(arch)-hermit-objcopy --strip-debug target/$(arch)-unknown-hermit/$(rdir)/hctests
  clean:
  @$(RM) target
  