--- a/memfd_create.c	(index)
+++ b/memfd_create.c	(working tree)
@@ -1,8 +1,9 @@
 #define _GNU_SOURCE 1
 #include <sys/mman.h>
 #include "syscall.h"
+#include <linux/unistd.h>
 
 int memfd_create(const char *name, unsigned flags)
 {
-	return syscall(SYS_memfd_create, name, flags);
+	return syscall(__NR_memfd_create, name, flags);
 }