diff --git a/libc/include/sched.h b/libc/include/sched.h
index ca72da7..4d7d8c6 100644
--- a/libc/include/sched.h
+++ b/libc/include/sched.h
@@ -71,6 +71,7 @@
 
 #ifdef _GNU_SOURCE
 extern int clone(int (*fn)(void *), void *child_stack, int flags, void*  arg, ...);
+extern int unshare(int);
 #endif
 
 /* Support for cpu thread affinity */