support *.cxx for c++ files
support *.cxx for c++ files

tboox/xmake,waruqi/xmake,waruqi/xmake,tboox/xmake,waruqi/xmake,tboox/xmake,waruqi/xmake,tboox/xmake,waruqi/xmake,waruqi/xmake,waruqi/xmake,tboox/xmake,tboox/xmake,tboox/xmake