add openblas_getaffinity()

cblas.h

@@ -28,6 +28,8 @@ char* openblas_get_corename(void);
 #ifdef OPENBLAS_OS_LINUX
 /* Sets thread affinity for OpenBLAS threads. `thread_idx` is in [0, openblas_get_num_threads()-1]. */
 int openblas_setaffinity(int thread_idx, size_t cpusetsize, cpu_set_t* cpu_set);
+/* Queries thread affinity for OpenBLAS threads. `thread_idx` is in [0, openblas_get_num_threads()-1]. */
+int openblas_getaffinity(int thread_idx, size_t cpusetsize, cpu_set_t* cpu_set);
 #endif
 
 /* Get the parallelization type which is used by OpenBLAS */