Merge fixes for:

MDEV-4797 - Spider crash on show create table spider table and replication
            multi source to one of the partitions
MDEV-4747 - Spider: add missing install_spider.sql

storage/spider/CMakeLists.txt

+SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DHAVE_HANDLERSOCKET")
+SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DHAVE_HANDLERSOCKET")
+
 SET(SPIDER_SOURCES
   spd_param.cc spd_sys_table.cc spd_trx.cc spd_db_conn.cc spd_conn.cc
   spd_table.cc spd_direct_sql.cc spd_udf.cc spd_ping_table.cc
@@ -34,7 +37,11 @@ ELSE()
     ${CMAKE_SOURCE_DIR}/storage/spider/hs_client
     ${ORACLE_INCLUDE_DIR})
 
-  SET(SPIDER_DEB_FILES "usr/lib/mysql/plugin/ha_spider.so" PARENT_SCOPE)
+  INSTALL(FILES
+    ${CMAKE_SOURCE_DIR}/storage/spider/scripts/install_spider.sql
+    DESTINATION ${INSTALL_MYSQLSHAREDIR} COMPONENT Server
+  )
+  SET(SPIDER_DEB_FILES "usr/lib/mysql/plugin/ha_spider.so usr/share/mysql/install_spider.sql" PARENT_SCOPE)
   MYSQL_ADD_PLUGIN(spider ${SPIDER_SOURCES} STORAGE_ENGINE MODULE_ONLY MODULE_OUTPUT_NAME "ha_spider")
 ENDIF()
 

storage/spider/ha_spider.cc

@@ -11347,7 +11347,7 @@ int ha_spider::rnd_handler_init()
 
 void ha_spider::set_error_mode()
 {
-  THD *thd = trx->thd;
+  THD *thd = ha_thd();
   DBUG_ENTER("ha_spider::set_error_mode");
   DBUG_PRINT("info",("spider this=%p", this));
   switch (thd_sql_command(thd))