attach: Defined MS_REC and MS_SLAVE if not set

src/lxc/attach.c

@@ -64,6 +64,14 @@
 #  define SOCK_CLOEXEC                02000000
 #endif
 
+#ifndef MS_REC
+#define MS_REC 16384
+#endif
+
+#ifndef MS_SLAVE
+#define MS_SLAVE (1<<19)
+#endif
+
 lxc_log_define(lxc_attach, lxc);
 
 static struct lxc_proc_context_info *lxc_proc_get_context_info(pid_t pid)

src/lxc/lxc_usernsexec.c

@@ -44,6 +44,14 @@
 #include "namespace.h"
 #include "utils.h"
 
+#ifndef MS_REC
+#define MS_REC 16384
+#endif
+
+#ifndef MS_SLAVE
+#define MS_SLAVE (1<<19)
+#endif
+
 int unshare(int flags);
 
 static void usage(const char *name)