Make xlog_internal.h includable in frontend context.

This makes unnecessary the ugly hack used to #include postgres.h in
pg_basebackup.

Based on Alvaro Herrera's patch

Author: hlinnaka

src/backend/access/rmgrdesc/xlogdesc.c

@@ -14,6 +14,7 @@
  */
 #include "postgres.h"
 
+#include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "catalog/pg_control.h"
 #include "utils/guc.h"

src/backend/access/transam/xlogarchive.c

@@ -20,6 +20,7 @@
 #include <signal.h>
 #include <unistd.h>
 
+#include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "miscadmin.h"
 #include "postmaster/startup.h"

src/backend/access/transam/xlogfuncs.c

@@ -18,6 +18,7 @@
 
 #include "access/htup_details.h"
 #include "access/xlog.h"
+#include "access/xlog_fn.h"
 #include "access/xlog_internal.h"
 #include "access/xlogutils.h"
 #include "catalog/catalog.h"

src/backend/postmaster/bgwriter.c

@@ -39,6 +39,7 @@
 #include <time.h>
 #include <unistd.h>
 
+#include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"

src/backend/postmaster/checkpointer.c

@@ -41,6 +41,7 @@
 #include <time.h>
 #include <unistd.h>
 
+#include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"

src/backend/postmaster/pgarch.c

@@ -32,6 +32,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"

src/bin/pg_basebackup/pg_basebackup.c

@@ -11,13 +11,7 @@
  *-------------------------------------------------------------------------
  */
 
-/*
- * We have to use postgres.h not postgres_fe.h here, because there's so much
- * backend-only stuff in the XLOG include files we need.  But we need a
- * frontend-ish environment otherwise.	Hence this ugly hack.
- */
-#define FRONTEND 1
-#include "postgres.h"
+#include "postgres_fe.h"
 #include "libpq-fe.h"
 
 #include <unistd.h>

src/bin/pg_basebackup/pg_receivexlog.c

@@ -12,13 +12,7 @@
  *-------------------------------------------------------------------------
  */
 
-/*
- * We have to use postgres.h not postgres_fe.h here, because there's so much
- * backend-only stuff in the XLOG include files we need.  But we need a
- * frontend-ish environment otherwise.	Hence this ugly hack.
- */
-#define FRONTEND 1
-#include "postgres.h"
+#include "postgres_fe.h"
 #include "libpq-fe.h"
 #include "libpq/pqsignal.h"
 #include "access/xlog_internal.h"

src/bin/pg_basebackup/receivelog.c

@@ -11,14 +11,7 @@
  *		  src/bin/pg_basebackup/receivelog.c
  *-------------------------------------------------------------------------
  */
-
-/*
- * We have to use postgres.h not postgres_fe.h here, because there's so much
- * backend-only stuff in the XLOG include files we need.  But we need a
- * frontend-ish environment otherwise.	Hence this ugly hack.
- */
-#define FRONTEND 1
-#include "postgres.h"
+#include "postgres_fe.h"
 
 #include <sys/stat.h>
 #include <sys/time.h>
@@ -30,8 +23,6 @@
 
 #include "libpq-fe.h"
 #include "access/xlog_internal.h"
-#include "utils/datetime.h"
-#include "utils/timestamp.h"
 
 #include "receivelog.h"
 #include "streamutil.h"

src/bin/pg_basebackup/streamutil.c

@@ -11,13 +11,7 @@
  *-------------------------------------------------------------------------
  */
 
-/*
- * We have to use postgres.h not postgres_fe.h here, because there's so much
- * backend-only stuff in the XLOG include files we need.  But we need a
- * frontend-ish environment otherwise.	Hence this ugly hack.
- */
-#define FRONTEND 1
-#include "postgres.h"
+#include "postgres_fe.h"
 #include "streamutil.h"
 
 #include <stdio.h>