ld: symbol(s) not found for architecture x86_64

I tried following the installation steps and encountered the below error while running 'make'. Any ideas?

```
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [benchmark/knn_table_benchmark] Error 1
make[1]: *** [benchmark/CMakeFiles/knn_table_benchmark.dir/all] Error 2
make: *** [all] Error 2
```