macosx: check for updates only every seven days

additionally, save the user's selection to check for updates as soon as it is changed, so we don't ask multiple times in case of a crash

modules/gui/macosx/update.m

@@ -36,7 +36,7 @@ static NSString * kPrefUpdateOnStartup = @"UpdateOnStartup";
 static NSString * kPrefUpdateLastTimeChecked = @"UpdateLastTimeChecked";
 
 /*****************************************************************************
- * VLCExtended implementation
+ * VLCUpdate implementation
  *****************************************************************************/
 
 @implementation VLCUpdate
@@ -85,6 +85,9 @@ static VLCUpdate *_o_sharedInstance = nil;
 {
     [[NSUserDefaults standardUserDefaults] setBool: check forKey: kPrefUpdateOnStartup];
     [o_chk_updateOnStartup setState: check];
+
+    /* make sure we got this set, even if we crash later on */
+    [[NSUserDefaults standardUserDefaults] synchronize];
 }
 
 - (BOOL)shouldCheckForUpdate
@@ -107,7 +110,7 @@ static VLCUpdate *_o_sharedInstance = nil;
     if( !o_last_update )
         return YES;
 
-    o_next_update = [[[NSDate alloc] initWithTimeInterval: 60*60*24*2 /* every two days */ sinceDate: o_last_update] autorelease];
+    o_next_update = [[[NSDate alloc] initWithTimeInterval: 60*60*24*7 /* every seven days */ sinceDate: o_last_update] autorelease];
     if( !o_next_update )
         return YES;