Move recovery injector astreamer to a separate header file.

Unlike the rest of the astreamer (formerly bbstreamer) infrastructure
which is reusable by other tools, astreamer_inject.c seems extremely
specific to pg_basebackup. Hence, move the corresponding declarations
to a separate header file, so that we can move the rest of the code
without moving this.

Amul Sul, reviewed by Sravan Kumar and by me.

Discussion: http://postgr.es/m/CAAJ_b94StvLWrc_p4q-f7n3OPfr6GhL8_XuAg2aAaYZp1tF-nw@mail.gmail.com

src/bin/pg_basebackup/astreamer.h

@@ -217,10 +217,4 @@ extern astreamer *astreamer_tar_parser_new(astreamer *next);
 extern astreamer *astreamer_tar_terminator_new(astreamer *next);
 extern astreamer *astreamer_tar_archiver_new(astreamer *next);
 
-extern astreamer *astreamer_recovery_injector_new(astreamer *next,
-												  bool is_recovery_guc_supported,
-												  PQExpBuffer recoveryconfcontents);
-extern void astreamer_inject_file(astreamer *streamer, char *pathname,
-								  char *data, int len);
-
 #endif

src/bin/pg_basebackup/astreamer_inject.c

@@ -11,7 +11,7 @@
 
 #include "postgres_fe.h"
 
-#include "astreamer.h"
+#include "astreamer_inject.h"
 #include "common/file_perm.h"
 #include "common/logging.h"
 

src/bin/pg_basebackup/astreamer_inject.h

@@ -0,0 +1,24 @@
+/*-------------------------------------------------------------------------
+ *
+ * astreamer_inject.h
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		  src/bin/pg_basebackup/astreamer_inject.h
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef ASTREAMER_INJECT_H
+#define ASTREAMER_INJECT_H
+
+#include "astreamer.h"
+#include "pqexpbuffer.h"
+
+extern astreamer *astreamer_recovery_injector_new(astreamer *next,
+												  bool is_recovery_guc_supported,
+												  PQExpBuffer recoveryconfcontents);
+extern void astreamer_inject_file(astreamer *streamer, char *pathname,
+								  char *data, int len);
+
+#endif

src/bin/pg_basebackup/pg_basebackup.c

@@ -26,7 +26,7 @@
 #endif
 
 #include "access/xlog_internal.h"
-#include "astreamer.h"
+#include "astreamer_inject.h"
 #include "backup/basebackup.h"
 #include "common/compression.h"
 #include "common/file_perm.h"