Refactor: Simplify num_cpu_avail() syntax

Author: nh2

common_thread.h

@@ -151,27 +151,17 @@ static __inline int num_cpu_avail(int level) {
     return blas_cpu_number;
   }
 
-int openmp_nthreads;
-	openmp_nthreads=omp_get_max_threads();
-	if (omp_in_parallel()) openmp_nthreads = blas_omp_threads_local;
-#endif
-
-#ifndef USE_OPENMP 
-  if (blas_cpu_number == 1
-#else
-     if (openmp_nthreads == 1 
-#endif
-      ) return 1;        
+  int openmp_nthreads = omp_in_parallel() ? blas_omp_threads_local : omp_get_max_threads();
 
-#ifdef USE_OPENMP
-     if (openmp_nthreads > blas_omp_number_max){
+  if (openmp_nthreads > blas_omp_number_max) {
 #ifdef DEBUG
-     fprintf(stderr,"WARNING - more OpenMP threads requested (%d) than available (%d)\n",openmp_nthreads,blas_omp_number_max);
+    fprintf(stderr, "WARNING - more OpenMP threads requested (%d) than available (%d)\n", openmp_nthreads, blas_omp_number_max);
 #endif
-     openmp_nthreads = blas_omp_number_max;
-     }
-     if (blas_cpu_number != openmp_nthreads) {
-	  goto_set_num_threads(openmp_nthreads);
+    openmp_nthreads = blas_omp_number_max;
+  }
+
+  if (blas_cpu_number != openmp_nthreads) {
+    goto_set_num_threads(openmp_nthreads); // mutates `blas_cpu_number`
   }
 #endif