pg_dump: Tiny header cleanup

In commits 9c02e3a and 8ec0aae, Nathan added a duplicate
TocEntry typedef forward declaration (plus assorted #ifdef hackery to
avoid C99 preprocessor issues) to deal with some very old untidyness
regarding DefnDumperPtr function prototype being located in pg_backup.h.
But there's no reason to have the DefnDumperPtr typedef (and the
accompanying DataDumperPtr typedef) in that file at all; they are better
placed in pg_backup_archiver.h, the internal header, because they are
only used internally.  That also requires zero #ifdef hackery, so move
them there.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/202504042140.qo66ggw6wzsz@alvherre.pgsql

Author: alvherre

src/bin/pg_dump/pg_backup.h

@@ -284,16 +284,6 @@ typedef int DumpId;
 /*
  * Function pointer prototypes for assorted callback methods.
  */
-
-/* forward declaration to avoid including pg_backup_archiver.h here */
-#ifndef HAVE_TOCENTRY_TYPEDEF
-typedef struct _tocEntry TocEntry;
-#define HAVE_TOCENTRY_TYPEDEF 1
-#endif
-
-typedef char *(*DefnDumperPtr) (Archive *AH, const void *userArg, const TocEntry *te);
-typedef int (*DataDumperPtr) (Archive *AH, const void *userArg);
-
 typedef void (*SetupWorkerPtrType) (Archive *AH);
 
 /*

src/bin/pg_dump/pg_backup_archiver.h

@@ -97,10 +97,7 @@
 #define WORKER_IGNORED_ERRORS		  12
 
 typedef struct _archiveHandle ArchiveHandle;
-#ifndef HAVE_TOCENTRY_TYPEDEF
 typedef struct _tocEntry TocEntry;
-#define HAVE_TOCENTRY_TYPEDEF 1
-#endif
 struct ParallelState;
 
 #define READ_ERROR_EXIT(fd) \
@@ -344,6 +341,10 @@ struct _archiveHandle
 	struct _tocEntry *lastErrorTE;
 };
 
+
+typedef char *(*DefnDumperPtr) (Archive *AH, const void *userArg, const TocEntry *te);
+typedef int (*DataDumperPtr) (Archive *AH, const void *userArg);
+
 struct _tocEntry
 {
 	struct _tocEntry *prev;