Fix condition variable clock ifdef

src/misc/threads.c

@@ -28,6 +28,9 @@
 
 #include "libvlc.h"
 #include <assert.h>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
 
 #define VLC_THREADS_UNINITIALIZED  0
 #define VLC_THREADS_PENDING        1
@@ -464,7 +467,7 @@ int __vlc_cond_init( vlc_object_t *p_this, vlc_cond_t *p_condvar )
     if (ret)
         return ret;
 
-# if defined (_POSIX_CLOCK_MONOTONIC) && (_POSIX_CLOCK_MONOTONIC >= 0)
+# if defined (_POSIX_MONOTONIC_CLOCK) && (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
     /* This must be the same clock as the one in mtime.c */
     pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
 # endif