Changed to include linux/sched.c for compiling on debian-stable.

netns.c

@@ -3,7 +3,7 @@
 */
 
 #include <stdio.h>
-#include <sched.h>
+#include <linux/sched.h>
 #include <unistd.h>
 
 int main(int argc, char *argv[])