[newlib-cygwin] Use #if __GNU_VISIBLE, not #ifdef __GNU_VISIBLE

[newlib-cygwin] Use #if __GNU_VISIBLE, not #ifdef __GNU_VISIBLE

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=58ede08b913a681de1958b91c4fbec84b875549a

commit 58ede08b913a681de1958b91c4fbec84b875549a
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Wed Aug 24 10:18:54 2016 +0200

    Use #if __GNU_VISIBLE, not #ifdef __GNU_VISIBLE
    
    sys/features.h always defines __GNU_VISIBLE, either as 0 or 1.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 newlib/libc/include/pthread.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/include/pthread.h b/newlib/libc/include/pthread.h
index 33ced0a..8206855 100644
--- a/newlib/libc/include/pthread.h
+++ b/newlib/libc/include/pthread.h
@@ -225,7 +225,7 @@ int	_EXFUN(pthread_attr_setguardsize,
  * in GNU/Linux. They may be provided by other OSes for
  * compatibility.
  */
-#if defined(__GNU_VISIBLE)
+#if __GNU_VISIBLE
 #if defined(__rtems__) 
 int	_EXFUN(pthread_attr_setaffinity_np,
 	(pthread_attr_t *__attr, size_t __cpusetsize, 
@@ -242,7 +242,7 @@ int	_EXFUN(pthread_getaffinity_np,
 int	_EXFUN(pthread_getattr_np,
 	(pthread_t __id, pthread_attr_t *__attr));
 #endif /* defined(__rtems__) */
-#endif /* defined(__GNU_VISIBLE) */
+#endif /* __GNU_VISIBLE */
 
 /* Thread Creation, P1003.1c/Draft 10, p. 144 */