Remove unused #include's from backend .c files

as determined by include-what-you-use (IWYU)

While IWYU also suggests to *add* a bunch of #include's (which is its
main purpose), this patch does not do that.  In some cases, a more
specific #include replaces another less specific one.

Some manual adjustments of the automatic result:

- IWYU currently doesn't know about includes that provide global
  variable declarations (like -Wmissing-variable-declarations), so
  those includes are being kept manually.

- All includes for port(ability) headers are being kept for now, to
  play it safe.

- No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the
  patch from exploding in size.

Note that this patch touches just *.c files, so nothing declared in
header files changes in hidden ways.

As a small example, in src/backend/access/transam/rmgr.c, some IWYU
pragma annotations are added to handle a special case there.

Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org

src/backend/utils/cache/catcache.c

@@ -17,11 +17,9 @@
 #include "access/genam.h"
 #include "access/heaptoast.h"
 #include "access/relscan.h"
-#include "access/sysattr.h"
 #include "access/table.h"
 #include "access/xact.h"
 #include "catalog/pg_collation.h"
-#include "catalog/pg_operator.h"
 #include "catalog/pg_type.h"
 #include "common/hashfn.h"
 #include "common/pg_prng.h"

src/backend/utils/cache/evtcache.c

@@ -28,7 +28,6 @@
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
-#include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
 typedef enum

src/backend/utils/cache/inval.c

@@ -119,7 +119,6 @@
 #include "storage/sinval.h"
 #include "storage/smgr.h"
 #include "utils/catcache.h"
-#include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/memdebug.h"
 #include "utils/memutils.h"

src/backend/utils/cache/lsyscache.c

@@ -17,20 +17,22 @@
 
 #include "access/hash.h"
 #include "access/htup_details.h"
-#include "access/nbtree.h"
 #include "bootstrap/bootstrap.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_amop.h"
 #include "catalog/pg_amproc.h"
 #include "catalog/pg_cast.h"
+#include "catalog/pg_class.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_constraint.h"
+#include "catalog/pg_index.h"
 #include "catalog/pg_language.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_proc.h"
+#include "catalog/pg_publication.h"
 #include "catalog/pg_range.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_subscription.h"
@@ -44,7 +46,6 @@
 #include "utils/datum.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
-#include "utils/rel.h"
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 

src/backend/utils/cache/partcache.c

@@ -19,7 +19,6 @@
 #include "access/nbtree.h"
 #include "access/relation.h"
 #include "catalog/partition.h"
-#include "catalog/pg_inherits.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_partitioned_table.h"
 #include "miscadmin.h"
@@ -27,9 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
-#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
-#include "utils/datum.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/partcache.h"

src/backend/utils/cache/plancache.c

@@ -63,7 +63,6 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "parser/analyze.h"
-#include "parser/parsetree.h"
 #include "storage/lmgr.h"
 #include "tcop/pquery.h"
 #include "tcop/utility.h"

src/backend/utils/cache/relcache.c

@@ -32,7 +32,6 @@
 
 #include "access/htup_details.h"
 #include "access/multixact.h"
-#include "access/nbtree.h"
 #include "access/parallel.h"
 #include "access/reloptions.h"
 #include "access/sysattr.h"
@@ -40,7 +39,6 @@
 #include "access/tableam.h"
 #include "access/tupdesc_details.h"
 #include "access/xact.h"
-#include "access/xlog.h"
 #include "catalog/binary_upgrade.h"
 #include "catalog/catalog.h"
 #include "catalog/indexing.h"

src/backend/utils/cache/relfilenumbermap.c

@@ -19,12 +19,10 @@
 #include "catalog/pg_class.h"
 #include "catalog/pg_tablespace.h"
 #include "miscadmin.h"
-#include "utils/builtins.h"
 #include "utils/catcache.h"
 #include "utils/fmgroids.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
-#include "utils/rel.h"
 #include "utils/relfilenumbermap.h"
 #include "utils/relmapper.h"
 

src/backend/utils/cache/relmapper.c

@@ -46,7 +46,6 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
-#include "catalog/catalog.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/storage.h"
 #include "miscadmin.h"

src/backend/utils/cache/syscache.c

@@ -21,7 +21,6 @@
 #include "postgres.h"
 
 #include "access/htup_details.h"
-#include "access/sysattr.h"
 #include "catalog/pg_db_role_setting_d.h"
 #include "catalog/pg_depend_d.h"
 #include "catalog/pg_description_d.h"

src/backend/utils/cache/typcache.c

@@ -70,7 +70,6 @@
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
-#include "utils/snapmgr.h"
 #include "utils/syscache.h"
 #include "utils/typcache.h"