+ /* Considering all platforms with USE_POSIX_THREADS_WEAK, only few symbols
+ can be used to determine whether libpthread is in use. These are:
+ pthread_mutexattr_gettype
+ pthread_rwlockattr_destroy
+ pthread_rwlockattr_init
+ */
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() (pthread_mutexattr_gettype != NULL)