[newlib-cygwin] Cygwin: pthread_yield: Add BSD visibility

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=8b85b3c3adb85cd1e854de0e35db7c682b945702

commit 8b85b3c3adb85cd1e854de0e35db7c682b945702
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Sat Aug 29 21:09:33 2020 +0200

    Cygwin: pthread_yield: Add BSD visibility
    
    pthread_yield was only declared under GNU visibility,
    but the function should be available under BSD visibility
    as well.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/include/pthread.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/winsup/cygwin/include/pthread.h b/winsup/cygwin/include/pthread.h
index 4ef3aeab7..327926ced 100644
--- a/winsup/cygwin/include/pthread.h
+++ b/winsup/cygwin/include/pthread.h
@@ -234,6 +234,8 @@ int pthread_setname_np (pthread_t, const char *) __attribute__((__nonnull__(2)))
 int pthread_sigqueue (pthread_t *, int, const union sigval);
 int pthread_timedjoin_np (pthread_t, void **, const struct timespec *);
 int pthread_tryjoin_np (pthread_t, void **);
+#endif
+#if __BSD_VISIBLE || __GNU_VISIBLE
 int pthread_yield (void);
 #endif
 #if __MISC_VISIBLE /* HP-UX, others? */