make:collect2: error: ld returned 1 exit status

[zhang-stone100]

hi
i have downloaded the zipped project and unzipped it .
then , upon running "make" ,i get the error :

make
g++ -std=c++14 -c -o Contract.o Contract.cpp
g++ -std=c++14 -c -o Debug.o Debug.cpp
g++ -std=c++14 -c -o Disassm.o Disassm.cpp
g++ -std=c++14 -c -o Instruction.o Instruction.cpp
g++ -std=c++14 -c -o Output.o Output.cpp
g++ -std=c++14 -c -o Porosity.o Porosity.cpp
g++ -std=c++14 -c -o SHA3.o SHA3.cpp
g++ -std=c++14 -c -o Statement.o Statement.cpp
g++ -std=c++14 -c -o Utils.o Utils.cpp
g++ -std=c++14 -c -o VMState.o VMState.cpp
g++ -std=c++14 BasicBlocks.o CommonData.o Contract.o Debug.o Disassm.o Instruction.o Output.o Porosity.o SHA3.o Statement.o Utils.o VMState.o -o porosity
Porosity.o: In function parse(int, char**, _Arguments*)': Porosity.cpp:(.text+0x342): undefined reference to dev::fromHex(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, dev::WhenError)'
Porosity.cpp:(.text+0x4c8): undefined reference to dev::fromHex(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, dev::WhenError)' Porosity.cpp:(.text+0x553): undefined reference to dev::fromHex(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, dev::WhenError)'
Porosity.cpp:(.text+0x6f2): undefined reference to dev::fromHex(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, dev::WhenError)' Porosity.cpp:(.text+0x733): undefined reference to dev::fromHex(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, dev::WhenError)'
Porosity.o:Porosity.cpp:(.text+0x947): more undefined references to `dev::fromHex(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, dev::WhenError)' follow
collect2: error: ld returned 1 exit status
make: *** [porosity] Error 1

operative system centos 7