修改cmakelist.txt，修复clang编译器默认关闭rtti问题

Author: rongliangtang

CMakeLists.txt

@@ -106,7 +106,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
 	list(APPEND SDK_COMPILER_FLAGS "/GR-")
 	endif()
 elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-	list(APPEND SDK_COMPILER_FLAGS "-fno-exceptions" "-fPIC" "-fno-rtti")
+	list(APPEND SDK_COMPILER_FLAGS "-fno-exceptions" "-fPIC")
 	if (NOT ENABLE_RTTI)
 	list(APPEND SDK_COMPILER_FLAGS "-fno-rtti")
 	endif()