update Base.h in MdePkg to check the _MSC_VER and define GLOBAL_REMOVE_IF_UNREFERENCED to nothing for VS2013 and higher tool chain tags. Cc: Liming Gao <liming.gao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com> Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>