flesh out HERK prototype

lapack/potrf/potrf_U_parallel.c

@@ -121,7 +121,7 @@ blasint CNAME(blas_arg_t *args, BLASLONG *range_m, BLASLONG *range_n, FLOAT *sa,
       HERK_THREAD_UC(&newarg, NULL, NULL, sa, sb, 0);
 #else
       syrk_thread(mode | BLAS_TRANSA_N | BLAS_TRANSB_T,
-		  &newarg, NULL, NULL, (int (*)(void))HERK_UC, sa, sb, args -> nthreads);
+		  &newarg, NULL, NULL, (int (*)(blas_arg_t *, BLASLONG *, BLASLONG *, FLOAT *, FLOAT *, BLASLONG))HERK_UC, sa, sb, args -> nthreads);
 #endif
     }
   }