Merge isisd into the Quagga's framework:
  - add privs support
  - use misc quagga's definitions
  - make it compile"able"
  - fix segfault cases related to hostname()
  - add debug isis xxx command

This patch has been approved by Paul Jakma.
diff --git a/isisd/isis_misc.h b/isisd/isis_misc.h
index 0e219c6..ca0c0ae 100644
--- a/isisd/isis_misc.h
+++ b/isisd/isis_misc.h
@@ -53,6 +53,8 @@
  */
 int  speaks (struct nlpids *nlpids, int family);
 unsigned long isis_jitter (unsigned long timer, unsigned long jitter);
+const char * unix_hostname(void);
+
 
 /*
  * macros