Xcode6编译SDWebImage报错解决方法(SDWebImageDownloaderOperation.m错误)

报错：Use of undeclared identifier '_executing' / '_finished'；
解决方法：

在SDWebImageDownloaderOperation类的实现中(@implementation里)添加：

@synthesize executing = _executing;
@synthesize finished = _finished;

示例：

@implementation SDWebImageDownloaderOperation
{
    size_t width, height;
    BOOL responseFromCached;
}

@synthesize executing = _executing;
@synthesize finished = _finished;