httpd: Move starting the http server into C.

src/task.h

@@ -132,6 +132,14 @@ const char* tf_task_get_zip_path(tf_task_t* task);
 */
 const char* tf_task_get_root_path(tf_task_t* task);
 
+/**
+** Get the path to use for reading a given loose file.
+** @param task The task.
+** @param path The path to the file.
+** @return The path or NULL.  Free with tf_free().
+*/
+const char* tf_task_get_path_with_root(tf_task_t* task, const char* path);
+
 /**
 ** Set arbitrary named arguments that will be made available to the task.
 ** @param task The task.