add configure option to use clang
add configure option to use clang

Change-Id: Ide63ef8bde7ed739b9bf29e936c01e156e8e3de4

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core