fixed libtools portability bug, fixed arc4random() portability,

fixed htobe32 and be32toh portability, fixed error handling in main(),
fixed invalid type parameter for randomart image in pcppubkey_printshortinfo(),
fixed configure search for libsodium.

libpcp/vault.h

@@ -8,6 +8,7 @@
 #include <unistd.h>
 
 #include "defines.h"
+#include "platform.h"
 #include "mem.h"
 #include "key.h"
 #include "uthash.h"