diff -uNr lxc-3.1.0/src/include/lxcmntent.c lxc-3.1.0.mod/src/include/lxcmntent.c
--- lxc-3.1.0/src/include/lxcmntent.c	2018-12-14 01:13:51.000000000 +0200
+++ lxc-3.1.0.mod/src/include/lxcmntent.c	2019-07-13 19:04:12.908102863 +0300
@@ -25,6 +25,7 @@
 #include <mntent.h>
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 #include "../lxc/macro.h"
 
 /* Since the values in a line are separated by spaces, a name cannot
