cmake undefined reference to `pthread_create' installing Caffe2

Question

I am installing Caffe2 from this Caffe2. When I run the cmake command I get this error :

cmake -DCUDNN_INCLUDE_DIR=~/cuda/include -DCUDNN_LIBRARY=~/cuda/lib64/libcudnn.so  -DCUDA_HOST_COMPILER=/usr/bin/gcc-5 -DUSE_NNPACK=OFF -DCMAKE_PREFIX_PATH=~/anaconda3/envs/caffe2 -DCMAKE_INSTALL_PREFIX=~/anaconda3/envs/caffe2 ..

cmake undefined reference to `pthread_create' I am using:
ubuntu 18.0.4
anconda3
cmake 3.10.0

ldconfig -p | grep pthread
    libpthread.so.0 (libc6,x86-64, OS ABI: Linux 3.2.0) => /lib/x86_64-linux-gnu/libpthread.so.0
    libpthread.so.0 (libc6, OS ABI: Linux 3.2.0) => /lib/i386-linux-gnu/libpthread.so.0