Backport pg_basebackup --slot option from 9.6 to 9.5

pg_basebackup.patch

--- src/bin/pg_basebackup/pg_basebackup_origin.c	2016-03-24 12:42:30.312362751 +0300
+++ src/bin/pg_basebackup/pg_basebackup.c	2016-03-24 09:45:40.804376436 +0300
@@ -239,6 +239,7 @@
 	  "                         (in kB/s, or use suffix \"k\" or \"M\")\n"));
 	printf(_("  -R, --write-recovery-conf\n"
 			 "                         write recovery.conf after backup\n"));
+	printf(_("  -S, --slot=SLOTNAME    replication slot to use\n"));
 	printf(_("  -T, --tablespace-mapping=OLDDIR=NEWDIR\n"
 	  "                         relocate tablespace in OLDDIR to NEWDIR\n"));
 	printf(_("  -x, --xlog             include required WAL files in backup (fetch mode)\n"));
@@ -1526,6 +1527,13 @@
 	appendPQExpBuffer(recoveryconfcontents, "primary_conninfo = '%s'\n", escaped);
 	free(escaped);
 
+	if (replication_slot)
+ 	{
+ 		escaped = escape_quotes(replication_slot);
+ 		appendPQExpBuffer(recoveryconfcontents, "primary_slot_name = '%s'\n", replication_slot);
+		free(escaped);
+ 	}
+
 	if (PQExpBufferBroken(recoveryconfcontents) ||
 		PQExpBufferDataBroken(conninfo_buf))
 	{
@@ -1924,6 +1932,7 @@
 		{"checkpoint", required_argument, NULL, 'c'},
 		{"max-rate", required_argument, NULL, 'r'},
 		{"write-recovery-conf", no_argument, NULL, 'R'},
+		{"slot", required_argument, NULL, 'S'},
 		{"tablespace-mapping", required_argument, NULL, 'T'},
 		{"xlog", no_argument, NULL, 'x'},
 		{"xlog-method", required_argument, NULL, 'X'},
@@ -1964,7 +1973,8 @@
 		}
 	}
 
-	while ((c = getopt_long(argc, argv, "D:F:r:RT:xX:l:zZ:d:c:h:p:U:s:wWvP",
+
+	while ((c = getopt_long(argc, argv, "D:F:r:RT:xX:l:zZ:d:c:h:p:U:s:S:wWvP",
 							long_options, &option_index)) != -1)
 	{
 		switch (c)
@@ -1991,6 +2001,9 @@
 			case 'R':
 				writerecoveryconf = true;
 				break;
+			case 'S':
+ 				replication_slot = pg_strdup(optarg);
+ 				break;
 			case 'T':
 				tablespace_list_append(optarg);
 				break;
@@ -2154,7 +2167,15 @@
 				progname);
 		exit(1);
 	}
-
+	if (replication_slot && !streamwal)
+ 	{
+ 		fprintf(stderr,
+ 				_("%s: replication slots can only be used with WAL streaming\n"),
+ 				progname);
+ 		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+ 				progname);
+ 		exit(1);
+ 	}
 	if (strcmp(xlog_dir, "") != 0)
 	{
 		if (format != 'p')