修复windows下编译错误

src/Http/HttpBody.cpp

@@ -72,10 +72,10 @@ HttpFileBody::HttpFileBody(const std::shared_ptr<FILE> &fp, size_t offset, size_
 #endif
 
 int HttpFileBody::sendFile(int fd) {
+#if defined(__linux__) || defined(__linux)
     static onceToken s_token([]() {
         signal(SIGPIPE, SIG_IGN);
     });
-#if  defined(__linux__) || defined(__linux)
     off_t off = _file_offset;
     return sendfile(fd, fileno(_fp.get()), &off, _max_size);
 #else