I install gcc-5
conda install -c salford_systems gcc-5

Then It errors like this just as what @Ben_Harper says
/home/xxx/anaconda3/compiler_compat/ld: cannot find -lcuda
/home/xxx/anaconda3/compiler_compat/ld: cannot find -lpthread
/home/xxx/anaconda3/compiler_compat/ld: cannot find -lc