Get macOS Application Support Folder from SDK.

SavePlace.mm

std::string getDocumentFolder()
{
  NSArray* paths = NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES);
  if ([paths count] == 0)
  {
    // Error.
    return std::string("");
  }

  NSString* applicationSupportDirectory = [NSString stringWithFormat:@"%@/%@",
                                                    [paths objectAtIndex:0],
                                                    [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleName"]];

  std::string path = [applicationSupportDirectory UTF8String];
}