Ensure include of sys/stat.h

It is required for mkdir(2), chmod(2) and mkfifo(2).

Signed-off-by: OBATA Akio <obache@wizdas.com>

tdm/backend/ctrl.c

@@ -41,6 +41,7 @@ from the copyright holder.
 #include <string.h>
 #include <signal.h>
 #include <pwd.h>
+#include <sys/stat.h>
 
 #ifdef __linux__
 #include <linux/vt.h>