Fix the build: UIButton and UIImageView are not defined on Mac OS or WatchOS

SDWebImage/UIView+WebCache.m

@@ -97,13 +97,17 @@ static char TAG_ACTIVITY_SHOW;
 - (void)sd_setImage:(UIImage *)image imageData:(NSData *)imageData basedOnClassOrViaCustomSetImageBlock:(SDSetImageBlock)setImageBlock {
     if (setImageBlock) {
         setImageBlock(image, imageData);
-    } else if ([self isKindOfClass:[UIImageView class]]) {
+        return;
+    }
+#if SD_UIKIT
+    if ([self isKindOfClass:[UIImageView class]]) {
         UIImageView *imageView = (UIImageView *)self;
         imageView.image = image;
     } else if ([self isKindOfClass:[UIButton class]]) {
         UIButton *button = (UIButton *)self;
         [button setImage:image forState:UIControlStateNormal];
     }
+#endif
 }
 
 - (void)sd_setNeedsLayout {