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/lib/log.c b/lib/log.c
index aedab3c..5f6b32f 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -37,6 +37,7 @@
   "OSPF",
   "RIPNG",
   "OSPF6",
+  "ISIS",
   "MASC",
   NULL,
 };