[#23858] build: fix ./yb_build.sh release --gcc11

Summary:
Fix various compilation issues with this build configuration:

ybtidbitmap.h:

    ../../../../../../../src/postgres/src/include/nodes/ybtidbitmap.h:49:9: error: ‘unused’ attribute ignored [-Werror=attributes]
       49 |         YbTBMIteratingState iterating PG_USED_FOR_ASSERTS_ONLY;
          |         ^~~~~~~~~~~~~~~~~~~

pg_client_session.cc:

    ../../src/yb/common/schema.h: In member function ‘yb::Status yb::tserver::PgClientSession::AlterTable(const yb::tserver::PgAlterTableRequestPB&, yb::tserver::PgAlterTableResponsePB*, yb::rpc::RpcContext*)’:
    ../../src/yb/common/schema.h:475:28: error: ‘replica_identity’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
      475 |     ysql_replica_identity_ = replica_identity;
          |     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
    ../../src/yb/tserver/pg_client_session.cc:818:23: note: ‘replica_identity’ was declared here
      818 |     PgReplicaIdentity replica_identity;
          |                       ^~~~~~~~~~~~~~~~

cron.c:

    ../../src/odyssey/sources/cron.c: In function ‘od_cron_stat_cb’:
    ../../src/odyssey/sources/cron.c:67:25: error: ‘strncpy’ specified bound 64 equals destination size [-Werror=stringop-truncation]
       67 |                         strncpy(instance->yb_stats[index].user_name,
          |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       68 |                                 route->id.user, USER_NAME_MAX_LEN);
          |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../../src/odyssey/sources/cron.c:67:25: error: ‘strncpy’ specified bound 64 equals destination size [-Werror=stringop-truncation]
    ../../src/odyssey/sources/cron.c:67:25: error: ‘strncpy’ specified bound 64 equals destination size [-Werror=stringop-truncation]

yb-admin-snapshot-schedule-test.cc:

    ../../src/yb/tools/yb-admin-snapshot-schedule-test.cc: In lambda function:
    ../../src/yb/tools/yb-admin-snapshot-schedule-test.cc:269:56: error: ‘state’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
      269 |       return state == master::SysCloneStatePB::ABORTED ||
          |                                                        ^~
    In file included from ../../src/yb/util/result.h:23,
                     from ../../src/yb/util/enums.h:32,
                     from ../../src/yb/cdc/cdc_types.h:25,
                     from ../../src/yb/client/client_fwd.h:26,
                     from ../../src/yb/tools/yb-admin-snapshot-schedule-test.cc:24:
    ../../src/yb/tools/yb-admin-snapshot-schedule-test.cc:266:38: note: ‘state’ was declared here
      266 |       master::SysCloneStatePB::State state;
          |                                      ^~~~~

The cron.c change is an improvement.  The ybtidbitmap.h change is not
desirable (it should be reverted if future compiler versions are
smarter).  The remaining changes are not logically necessary either, but
they had to be changed because this build configuration complains.
Jira: DB-12765

Test Plan:
    ./yb_build.sh release --gcc11

Close: #23858
Jenkins: compile only

Reviewers: telgersma

Reviewed By: telgersma

Subscribers: telgersma, yql, ybase

Differential Revision: https://phorge.dev.yugabyte.com/D37829

src/odyssey/sources/cron.c

@@ -61,10 +61,10 @@ static int od_cron_stat_cb(od_route_t *route, od_stat_t *current,
  }
 
  index = route->id.yb_stats_index;
- strncpy(instance->yb_stats[index].database_name,
+ memcpy(instance->yb_stats[index].database_name,
  (char *)route->yb_database_entry->name,
  DB_NAME_MAX_LEN);
- strncpy(instance->yb_stats[index].user_name,
+ memcpy(instance->yb_stats[index].user_name,
  route->id.user, USER_NAME_MAX_LEN);
  }
 

src/postgres/src/include/nodes/ybtidbitmap.h

@@ -46,7 +46,7 @@ typedef struct YbTIDBitmap
  NodeTag type; /* to make it a valid Node */
  SliceSet ybctid_set; /* C++ set that contains my ybctids */
  int nentries; /* number of entries in the bitmap */
- YbTBMIteratingState iterating PG_USED_FOR_ASSERTS_ONLY;
+ YbTBMIteratingState iterating;
  /* yb_tbm_begin_iterate called? */
  size_t bytes_consumed; /* sum of the size of the ybctids */
  bool work_mem_exceeded; /* if bytes_consumed exceeds work_mem */

src/yb/tools/yb-admin-snapshot-schedule-test.cc

@@ -263,7 +263,7 @@ class YbAdminSnapshotScheduleTest : public AdminTestBase {
  CallJsonAdmin("list_clones", source_namespace_id, seq_no));
  const auto entries = out.GetArray();
  SCHECK_EQ(entries.Size(), 1, IllegalState, "Wrong number of entries. Expected 1");
- master::SysCloneStatePB::State state;
+ master::SysCloneStatePB::State state = master::SysCloneStatePB::CLONE_SCHEMA_STARTED;
  master::SysCloneStatePB::State_Parse(
  std::string(VERIFY_RESULT(GetMemberAsStr(entries[0], "aggregate_state"))), &state);
  return state == master::SysCloneStatePB::ABORTED ||

src/yb/tserver/pg_client_session.cc

@@ -825,7 +825,7 @@ Status PgClientSession::AlterTable(
  client::YBTablePtr yb_table;
  RETURN_NOT_OK(GetTable(table_id, &table_cache_, &yb_table));
  auto table_properties = yb_table->schema().table_properties();
- PgReplicaIdentity replica_identity;
+ PgReplicaIdentity replica_identity = PgReplicaIdentity::DEFAULT;
  RETURN_NOT_OK(
  GetReplicaIdentityEnumValue(req.replica_identity().replica_identity(), &replica_identity));
  table_properties.SetReplicaIdentity(replica_identity);