diff --git configure configure
index 1c9655e..9f83176 100755
--- configure
+++ configure
@@ -682,6 +682,7 @@ Haiku)
   vhost_net="yes"
   vhost_scsi="yes"
   vhost_vsock="yes"
+  QEMU_CFLAGS="-D_XOPEN_SOURCE=500 $QEMU_CFLAGS"
   QEMU_INCLUDES="-I\$(SRC_PATH)/linux-headers -I$(pwd)/linux-headers $QEMU_INCLUDES"
 ;;
 esac