diff --git a/include/stdlib.h b/include/stdlib.h
index be4e76e..54d4504 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -21,6 +21,7 @@
 static __inline__ int abs(int __n) {
   return (__n < 0) ? -__n : __n;
 }
+__extern int system(const char * string);
 __extern int atexit(void (*)(void));
 __extern int on_exit(void (*)(int, void *), void *);
 __extern int atoi(const char *);