macosx: more approbiate locking suggested by fenrir

and fixed a small typo

modules/gui/macosx/intf.m

@@ -324,7 +324,7 @@ static VLCMain *_o_sharedMainInstance = nil;
         NSAlert *ourAlert;
         int i_returnValue;
         NSString *o_blabla;
-        if( MACOS_VERSION == 10.5f )
+        if( MACOS_VERSION == 10.4f )
             o_blabla = _NS("VLC's last release for your OS is the 0.9 series." );
         else if( MACOS_VERSION == 10.3f )
             o_blabla = _NS("VLC's last release for your OS is VLC 0.8.6i, which is prone to known security issues." );

modules/gui/macosx/playlist.m

@@ -575,9 +575,9 @@
 
     PL_LOCK;
     p_item = playlist_CurrentPlayingItem( p_playlist );
-    PL_UNLOCK;
     if( p_item == NULL )
     {
+        PL_UNLOCK;
         pl_Release( VLCIntf );
         return;
     }
@@ -601,6 +601,7 @@
 
     }
 
+    PL_UNLOCK;
     pl_Release( VLCIntf );
 }