Fix CMake warning in spider, in Windows ninja build

storage/spider/CMakeLists.txt

@@ -55,6 +55,9 @@ ELSE()
     DESTINATION ${INSTALL_MYSQLSHAREDIR} COMPONENT Server
   )
   MYSQL_ADD_PLUGIN(spider ${SPIDER_SOURCES} STORAGE_ENGINE MODULE_ONLY MODULE_OUTPUT_NAME "ha_spider")
+  IF(NOT TARGET spider)
+    RETURN()
+  ENDIF()
 ENDIF()
 
 IF(ORACLE_INCLUDE_DIR AND ORACLE_OCI_LIBRARY)