server: include uio.h for writev()

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/server.c b/server.c
index 020d1d7..884ff8e 100644
--- a/server.c
+++ b/server.c
@@ -11,6 +11,7 @@
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/un.h>
+#include <sys/uio.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>