macosx: respect 'playlist-autostart' (close #7272)

(cherry picked from commit dd212bfe22089604415aefa69b33cd8f354cd847)

NEWS

@@ -8,8 +8,9 @@ Access:
 Demux:
  * Fix use after free in sgimb
 
-MacOSX:
+Mac OS X:
  * Fix interface crashes
+ * Fix autostart playback option
 
 Translations:
  * update Welsh translation

modules/gui/macosx/intf.m

@@ -691,6 +691,13 @@ static VLCMain *_o_sharedMainInstance = nil;
     [o_mainwindow updateWindow];
     [o_mainwindow updateTimeSlider];
     [o_mainwindow updateVolumeSlider];
+
+    playlist_t * p_playlist = pl_Get(VLCIntf);
+    PL_LOCK;
+    BOOL kidsAround = p_playlist->p_local_category->i_children;
+    PL_UNLOCK;
+    if (kidsAround && var_GetBool(p_playlist, "playlist-autostart"))
+        [[self playlist] playItem:nil];
 }
 
 - (void)initStrings