Add WITH_XMSS, move to prevent conflicts.
Add #ifdef WITH_XMSS to ssh-xmss.c, move it in the other files to after
includes.h so it's less likely to conflict and will pick up WITH_XMSS if
added to config.h.
diff --git a/xmss_hash.c b/xmss_hash.c
index c8b2711..f90e056 100644
--- a/xmss_hash.c
+++ b/xmss_hash.c
@@ -1,4 +1,3 @@
-#ifdef WITH_XMSS
/*
hash.c version 20160722
Andreas Hülsing
@@ -7,6 +6,7 @@
*/
#include "includes.h"
+#ifdef WITH_XMSS
#include "xmss_hash_address.h"
#include "xmss_commons.h"