REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2415 Avoid using __clang__ to specify CLANGPDB because this macro is also defined in CLANG38 and this causes CLANG38 build failure. Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Liming Gao <liming.gao@intel.com> Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com>