Rearrange some headers to make sure that out nbase errno defines are seen early,

avoiding warning about symbol redefinitions. This is mostly moving "nmap.h" to
the top of the list.

MACLookup.cc

@@ -91,12 +91,13 @@
 
 /* $Id$ */
 
+#include "nmap.h"
+
 #include <map>
 
 /* Character pool memory allocation */
 #include "MACLookup.h"
 #include "NmapOps.h"
-#include "nmap.h"
 #include "nmap_error.h"
 #include "charpool.h"