Add EINTR and EAGAIN judge for accept (#1438)

* Add EINTR and EAGAIN judge for accept

* Add EINTR signal tests

* Cancel win32 and win64 compile on signal unittest

Co-authored-by: yukun.yu <yukun.yu@alibaba-inc.com>

httplib.h

@@ -5507,6 +5507,8 @@ inline bool Server::listen_internal() {
           // Try to accept new connections after a short sleep.
           std::this_thread::sleep_for(std::chrono::milliseconds(1));
           continue;
+        } else if (errno == EINTR || errno == EAGAIN) {
+          continue;
         }
         if (svr_sock_ != INVALID_SOCKET) {
           detail::close_socket(svr_sock_);