Parallel pragma ignored

Does the following mean compilation flags needs to be properly set? Does it cause any issues?

```
In file included from src/CoGAPS/src/GapsRunner.cpp:8:
src/CoGAPS/src/gibbs_sampler/AsynchronousGibbsSampler.h:105: warning: ignoring #pragma omp parallel [-Wunknown-pragmas]
  105 |         #pragma omp parallel for num_threads(nThreads)
      | 
```