First step in refactoring out the build running from the gui for later thread fiascos.

builder.hpp

@@ -1,6 +1,7 @@
 #pragma once
 #include "gui.hpp"
 #include "game_engine.hpp"
+#include <stdio.h>
 
 using std::string;
 
@@ -14,7 +15,7 @@ class Builder {
 
   Builder(GUI &g, GameEngine &engine);
 
-  void run_build();
+  void run_build(const string &line);
 
   void run();
 };