Simplify xpand CMakeLists.txt

We don't need the MSVC hacks used by Spider.

storage/xpand/CMakeLists.txt

 #*****************************************************************************
-# Copyright (c) 2019, MariaDB Corporation.
+# Copyright (c) 2020, MariaDB Corporation.
 #****************************************************************************/
 
-IF(MSVC)
-  # Temporarily disable "conversion from size_t .."
-  IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
-    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4267")
-  ENDIF()
-ENDIF()
-
-SET(XPAND_PLUGIN_STATIC  "xpand")
-SET(XPAND_PLUGIN_DYNAMIC "ha_xpand")
 SET(XPAND_SOURCES ha_xpand.cc xpand_connection.cc ha_xpand_pushdown.cc)
 MYSQL_ADD_PLUGIN(xpand ${XPAND_SOURCES} STORAGE_ENGINE)
-
-IF(MSVC)
-  IF (CMAKE_BUILD_TYPE STREQUAL "Debug")
-    ADD_CUSTOM_COMMAND(TARGET xpand
-                       POST_BUILD
-                       COMMAND if not exist ..\\..\\sql\\lib mkdir ..\\..\\sql\\lib\\plugin
-                       COMMAND copy Debug\\ha_xpand.dll ..\\..\\sql\\lib\\plugin\\ha_xpand.dll)
-  ENDIF()
-ENDIF()