Do not print start banner if stderr is not a TTY.

The user is not going to see the banner, and this tends to clutter
error logs (X server, cron jobs...) - not only on MacOS.
(cherry picked from commit 62f348b047c0c691c4a47970072522a66633f486)

bin/vlc.c

@@ -99,11 +99,11 @@ int main( int i_argc, const char *ppsz_argv[] )
 
     setlocale (LC_ALL, "");
 
-#ifndef __APPLE__
-    /* This clutters OSX GUI error logs */
-    fprintf( stderr, "VLC media player %s (revision %s)\n",
-             libvlc_get_version(), libvlc_get_changeset() );
-#endif
+    if (isatty (STDERR_FILENO))
+        /* This message clutters error logs. It is print it only on a TTY.
+         * Forunately, LibVLC prints version infos with -vv anyhow. */
+        fprintf (stderr, "VLC media player %s (revision %s)\n",
+                 libvlc_get_version(), libvlc_get_changeset());
 
     /* Synchronously intercepted POSIX signals.
      *