Fix to CMakeLists.txt which I never use.
Fix to CMakeLists.txt which I never use.

minhpqn/mlpack,stereomatchingkiss/mlpack,ajjl/mlpack,stereomatchingkiss/mlpack,chenmoshushi/mlpack,ersanliqiao/mlpack,theranger/mlpack,chenmoshushi/mlpack,thirdwing/mlpack,theranger/mlpack,ranjan1990/mlpack,ranjan1990/mlpack,lezorich/mlpack,bmswgnp/mlpack,ranjan1990/mlpack,bmswgnp/mlpack,ersanliqiao/mlpack,erubboli/mlpack,minhpqn/mlpack,thirdwing/mlpack,ersanliqiao/mlpack,stereomatchingkiss/mlpack,Azizou/mlpack,trungda/mlpack,palashahuja/mlpack,trungda/mlpack,darcyliu/mlpack,trungda/mlpack,thirdwing/mlpack,ajjl/mlpack,darcyliu/mlpack,BookChan/mlpack,ajjl/mlpack,lezorich/mlpack,darcyliu/mlpack,theranger/mlpack,BookChan/mlpack,lezorich/mlpack,BookChan/mlpack,minhpqn/mlpack,palashahuja/mlpack,erubboli/mlpack,datachand/mlpack,datachand/mlpack,erubboli/mlpack,Azizou/mlpack,bmswgnp/mlpack,datachand/mlpack,palashahuja/mlpack,chenmoshushi/mlpack,Azizou/mlpack