include postgres.h into some of our .h files to silence warnings

src/include/distributed/master_metadata_utility.h

@@ -14,6 +14,8 @@
 #ifndef MASTER_METADATA_UTILITY_H
 #define MASTER_METADATA_UTILITY_H
 
+#include "postgres.h"
+
 #include "access/heapam.h"
 #include "access/htup.h"
 #include "access/tupdesc.h"

src/include/distributed/metadata_cache.h

@@ -11,6 +11,8 @@
 #ifndef METADATA_CACHE_H
 #define METADATA_CACHE_H
 
+#include "postgres.h"
+
 #include "fmgr.h"
 #include "distributed/master_metadata_utility.h"
 #include "distributed/pg_dist_partition.h"

src/include/distributed/worker_protocol.h

@@ -14,6 +14,8 @@
 #ifndef WORKER_PROTOCOL_H
 #define WORKER_PROTOCOL_H
 
+#include "postgres.h"
+
 #include "fmgr.h"
 #include "distributed/shardinterval_utils.h"
 #include "lib/stringinfo.h"