message: One more attempt to fix FreeBSD
  It seems sysctl.h is not self-contained, as I get missing symbols in the
  header itself now. I am going to include all files that the file I moved
  this from included, and hope that is enough.
diff: // C Includes
  #include <errno.h>
  +#include <pthread.h>
  +#include <pthread_np.h>
  +#include <stdlib.h>
  #include <sys/sysctl.h>
  #include <sys/types.h>
  +#include <sys/user.h>
  // C++ Includes
  // Other libraries and framework includes
  