diff --git a/src/header/unistd/mod.rs b/src/header/unistd/mod.rs
index 259255e1a8..f2bce45388 100644
--- a/src/header/unistd/mod.rs
+++ b/src/header/unistd/mod.rs
@@ -26,6 +26,11 @@ use alloc::collections::LinkedList;
 
 pub use self::{brk::*, getopt::*, getpass::getpass, pathconf::*, sysconf::*};
 
+// Inclusion of ctermid() prototype marked as obsolescent since Issue 7, cf.
+// <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html>.
+// cuserid() marked legacy in Issue 5.
+pub use crate::header::stdio::{ctermid, cuserid};
+
 use super::errno::{E2BIG, ENOMEM};
 
 mod brk;