Fix some gcc 4.0 warnings.

diff --git a/server/request.c b/server/request.c
index 1fd19c1..6aa0072 100644
--- a/server/request.c
+++ b/server/request.c
@@ -488,7 +488,7 @@
     else if (event & POLLIN)
     {
         struct sockaddr_un dummy;
-        int len = sizeof(dummy);
+        unsigned int len = sizeof(dummy);
         int client = accept( get_unix_fd( master_socket->fd ), (struct sockaddr *) &dummy, &len );
         if (client == -1) return;
         if (sock->timeout)