these need active_state defined to link on OSX

temporary measure until active_state goes away entirely
diff --git a/ssh-keyscan.c b/ssh-keyscan.c
index 62dbd62..25a257c 100644
--- a/ssh-keyscan.c
+++ b/ssh-keyscan.c
@@ -77,6 +77,8 @@
 size_t read_wait_nfdset;
 int ncon;
 
+struct ssh *active_state = NULL; /* XXX needed for linking */
+
 /*
  * Keep a connection structure for each file descriptor.  The state
  * associated with file descriptor n is held in fdcon[n].