build fail

[ztwe]

Environment
cuda9.0
cudnn7.1

src/caffe/layers/human_att_data_layer.cpp:324:100: error: redeclaration of 'std::vector<std::__cxx11::basic_string<char> > caffe::HumanAttDataLayer<Dtype>::StrSplit(std::__cxx11::string&, std::__cxx11::string)' may not have default arguments [-fpermissive]
 std::vector<std::string> HumanAttDataLayer<Dtype>::StrSplit(std::string &str, std::string sep = ",")
                                                                                                    ^
Makefile:568: recipe for target '.build_release/src/caffe/layers/human_att_data_layer.o' failed
make: *** [.build_release/src/caffe/layers/human_att_data_layer.o] Error 1