Write HELLO memory map debug data to serial port

Rsconscript

@@ -162,7 +162,10 @@ hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
   env.add_builder(CheckThreadLocal)
   env.add_builder(HulkBinObj)
   env["sources"] = glob("src/hello/**/*.d")
-  env["sources"] += ["src/hulk/writef.d"]
+  env["sources"] += %w[
+    src/hulk/serial.d
+    src/hulk/writef.d
+  ]
   env["sources"] += glob("uefi-d/source/**/*.d")
   env.HulkBinObj("^/hulk_bin.S", hulk_env.expand("^/hulk.bin"))
   env.Object("^/hulk_bin.o", "^/hulk_bin.S")