cope with 64-bit time_t on 32-bit arches

--- upload-queue.c.orig	Wed Jul 20 14:46:49 2016
+++ upload-queue.c	Tue Aug  2 11:45:58 2016
@@ -86,7 +86,7 @@ static void upload_queue_write_entry(const char *entry
 
 	for (serial = 0; serial < ULONG_MAX; ++serial) {
 		free(name);
-		xasprintf(&name, "upload-queue/%lu%04lu", time(NULL), serial);
+		xasprintf(&name, "upload-queue/%llu%04lu", (long long)time(NULL), serial);
 		if (!config_exists(name))
 			break;
 	}