std::chrono about delta-mock HOT 1 OPEN

I found the following error while make
mock_Util.cc: In function ‘void initialise_random(long unsigned int)’:
mock_Util.cc:299:21: error: ‘std::chrono’ has not been declared
299 | seed = std::chrono::system_clock::now().time_since_epoch().count();
So I have added
#include "chrono"
in mock_Util.cc file (it depends on the project, I was working on a different project).
Now the problem gets solved.
vinaysingh@vinaysingh-VirtualBox:~/delta/Delta-MOCK-master/Sources$ make all g++ -std=c++11 -O3 -c mock_Util.cc
g++ -std=c++11 -O3 -c mock_ClusteringProblem.cc
g++ -std=c++11 -O3 -c mock_Clustering.cc
g++ -std=c++11 -O3 -c mock_SolutionLocus.cc
g++ -std=c++11 -O3 -c mock_SolutionShort.cc
g++ -std=c++11 -O3 -c mock_SolutionSplit.cc
g++ -std=c++11 -O3 -c mock_Population.cc
g++ -std=c++11 -O3 -c mock_EvaluatorFull.cc
g++ -std=c++11 -O3 -c mock_BinaryOperator.cc
g++ -std=c++11 -O3 -c mock_UnaryOperator.cc
g++ -std=c++11 -O3 -c mock_Nsga2.cc
g++ -std=c++11 -O3 -c mock_EvaluatorDelta.cc
g++ -std=c++11 -O3 mock.o mock_Util.o mock_ClusteringProblem.o mock_Clustering.o mock_SolutionLocus.o mock_SolutionShort.o mock_SolutionSplit.o mock_Population.o mock_EvaluatorFull.o mock_BinaryOperator.o mock_UnaryOperator.o mock_Nsga2.o mock_EvaluatorDelta.o -o delta_mock

from delta-mock.