repmgrd: in BDR mode, have each repmgrd monitor each node

This will cover both the case when an entire node including
repmgrd goes down, and when one PostgreSQL instance goes down
but repmgrd is still up (in which case only one of the repmgrds
will handle the failover).

dbutils.h

@@ -9,6 +9,7 @@
 
 #include "access/xlogdefs.h"
 #include "pqexpbuffer.h"
+#include "portability/instr_time.h"
 
 #include "config.h"
 #include "strutil.h"
@@ -40,8 +41,10 @@ typedef enum {
 	RECORD_NOT_FOUND
 } RecordStatus;
 
-
-
+typedef enum {
+	MS_NORMAL = 0,
+	MS_DEGRADED = 1
+} MonitoringState;
 
 /*
  * Struct to store node information
@@ -62,6 +65,7 @@ typedef struct s_node_info
 	bool		  is_ready;
 	bool		  is_visible;
 	XLogRecPtr	  last_wal_receive_lsn;
+	MonitoringState monitoring_state;
 	PGconn		 *conn;
 }	t_node_info;
 
@@ -80,6 +84,7 @@ typedef struct s_node_info
   false, \
   false, \
   InvalidXLogRecPtr, \
+  MS_NORMAL, \
   NULL \
 }
 
@@ -323,5 +328,7 @@ void		 add_extension_tables_to_bdr_replication_set(PGconn *conn);
 
 bool		 bdr_node_exists(PGconn *conn, const char *node_name);
 
+bool		 am_bdr_failover_handler(PGconn *conn, int node_id);
+void		 unset_bdr_failover_handler(PGconn *conn);
 #endif /* dbutils.h */