Fix compiler warnings:
os/os0file.c: In function 'os_file_create':
os/os0file.c:1371:14: error: variable 'purpose_str' set but not used [-Werror=unused-but-set-variable]
os/os0file.c:1370:14: error: variable 'type_str' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
log/log0recv.c: In function 'recv_synchronize_groups':
log/log0recv.c:562:14: error: variable 'limit_lsn' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
log/log0recv.c: In function 'recv_recovery_from_checkpoint_start_func':
log/log0recv.c:2894:14: error: variable 'archived_lsn' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
handler/i_s.cc: In function 'int trx_i_s_common_fill_table(THD*, TABLE_LIST*, COND*)':
handler/i_s.cc:931:8: error: variable 'ret' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
handler/ha_innodb.cc: In function 'void innobase_drop_database(handlerton*, char*)':
handler/ha_innodb.cc:7010:6: error: variable 'error' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
handler/ha_innodb.cc: In function 'bool innodb_show_status(handlerton*, THD*, bool (*)(THD*, const char*, uint, const char*, uint, const char*, uint))':
handler/ha_innodb.cc:8851:7: error: variable 'result' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
eval/eval0eval.c: In function 'eval_notfound':
eval/eval0eval.c:388:14: error: variable 'arg2' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
dict/dict0dict.c: In function 'dict_index_print_low':
dict/dict0dict.c:4444:14: error: variable 'type_string' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
dict/dict0crea.c: In function 'dict_create_index_tree_step':
dict/dict0crea.c:630:16: error: variable 'table' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
buf/buf0flu.c: In function 'buf_flush_batch':
buf/buf0flu.c:1274:9: error: variable 'old_page_count' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
buf/buf0flu.c: In function 'buf_flush_delete_from_flush_rbt':
buf/buf0flu.c:131:8: error: variable 'ret' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0sea.c: In function 'btr_search_update_hash_on_delete':
btr/btr0sea.c:1498:9: error: variable 'found' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0pcur.c: In function 'btr_pcur_move_backward_from_page':
btr/btr0pcur.c:455:9: error: variable 'space' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0cur.c: In function 'btr_free_externally_stored_field':
btr/btr0cur.c:4281:16: error: variable 'rec_block' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0cur.c: In function 'btr_cur_optimistic_update':
btr/btr0cur.c:1839:10: error: variable 'orig_rec' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0btr.c: In function 'btr_compress':
btr/btr0btr.c:2564:9: error: variable 'level' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
btr/btr0btr.c: In function 'btr_page_split_and_insert':
btr/btr0btr.c:1898:11: error: variable 'insert_page' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
./include/ut0rnd.ic: In function 'ut_rnd_gen_ulint':
./include/ut0rnd.ic:88:8: error: variable 'n_bits' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
handler/ha_innodb.cc: In function 'bool innodb_show_status(handlerton*, THD*, bool (*)(THD*, const char*, uint, const char*, uint, const char*, uint))':
handler/ha_innodb.cc:7539:7: error: variable 'result' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
handler/ha_innodb.cc: In function 'void innobase_drop_database(handlerton*, char*)':
handler/ha_innodb.cc:5969:6: error: variable 'error' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0undo.c: In function 'trx_undo_set_state_at_prepare':
trx/trx0undo.c:1798:16: error: variable 'page_hdr' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0undo.c: In function 'trx_undo_truncate_end':
trx/trx0undo.c:1015:14: error: variable 'rseg' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0trx.c: In function 'trx_prepare_off_kernel':
trx/trx0trx.c:1830:11: error: variable 'update_hdr_page' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0sys.c: In function 'trx_sys_create_doublewrite_buf':
trx/trx0sys.c:168:10: error: variable 'new_page' set but not used [-Werror=unused-but-set-variable]

Fix compiler warnings:
trx/trx0roll.c: In function 'trx_undo_arr_remove_info':
trx/trx0roll.c:717:9: error: variable 'n' set but not used [-Werror=unused-but-set-variable]
trx/trx0roll.c:716:9: error: variable 'n_used' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0purge.c: In function 'trx_purge_rec_release':
trx/trx0purge.c:1007:18: error: variable 'arr' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0purge.c: In function 'trx_purge_rseg_get_next_history_log':
trx/trx0purge.c:599:15: error: variable 'seg_hdr' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
trx/trx0purge.c: In function 'trx_purge_add_update_undo_to_history':
trx/trx0purge.c:254:16: error: variable 'page_header' set but not used [-Werror=unused-but-set-variable]
trx/trx0purge.c:252:15: error: variable 'seg_header' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
row/row0vers.c: In function 'row_vers_impl_x_locked_off_kernel':
row/row0vers.c:62:9: error: variable 'err' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
row/row0upd.c: In function 'row_upd_in_place_in_select':
row/row0upd.c:2040:9: error: variable 'err' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
row/row0umod.c: In function 'row_undo_mod_clust_low':
row/row0umod.c:92:9: error: variable 'success' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
row/row0purge.c: In function 'row_purge_step':
row/row0purge.c:660:9: error: variable 'err' set but not used [-Werror=unused-but-set-variable]

(row_purge() always returns DB_SUCCESS)

Fix compiler warning:
que/que0que.c: In function 'que_thr_dec_refer_count':
que/que0que.c:805:11: error: variable 'sess' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
que/que0que.c: In function 'que_run_threads_low':
que/que0que.c:1295:9: error: variable 'cumul_resource' set but not used [-Werror=unused-but-set-variable]

Fix compiler warnings:
os/os0file.c: In function 'os_file_create':
os/os0file.c:1318:14: error: variable 'purpose_str' set but not used [-Werror=unused-but-set-variable]
os/os0file.c:1317:14: error: variable 'type_str' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
log/log0recv.c: In function 'recv_synchronize_groups':
log/log0recv.c:403:10: error: variable 'limit_lsn' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
log/log0recv.c: In function 'recv_recovery_from_checkpoint_start':
log/log0recv.c:2509:10: error: variable 'archived_lsn' set but not used [-Werror=unused-but-set-variable]

Fix compiler warning:
lock/lock0lock.c: In function 'lock_print_info_all_transactions':
lock/lock0lock.c:4299:10: error: variable 'page' set but not used [-Werror=unused-but-set-variable]