$ gcc --version
gcc (Ubuntu 6.3.0-12ubuntu2) 6.3.0 20170406
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

----

In all config.mk

-export NVCC = nvcc
+export NVCC = nvcc -ccbin gcc-4.9 -std=c++11

-ADD_LDFLAGS =
+ADD_LDFLAGS = -lopenblas

-USE_CUDA = 0
+USE_CUDA = 1

-USE_CUDA_PATH = NONE
+USE_CUDA_PATH = /usr/local/cuda

-USE_CUDNN = 0
+USE_CUDNN = 1

make NVCCFLAGS="-ccbin gcc-4.9 -std=c++11" -j6