Bits and pieces, mostly stubs, for the Mac port.

[originally from svn r5136]

mac/macnoise.c

@@ -67,6 +67,15 @@ void noise_get_light(void (*func) (void *, int))
     func(&utc, sizeof(utc));
 }
 
+/*
+ * This function is called on a timer, and grabs as much changeable
+ * system data as it can quickly get its hands on.
+ */
+void noise_regular(void)
+{
+    /* XXX */
+}
+
 /*
  * This function is called on every keypress or mouse move, and
  * will add the current time to the noise pool. It gets the scan