diff --git a/libc/libc.x86.brillo.map b/libc/libc.x86.brillo.map
index eb99079..c67f533 100644
--- a/libc/libc.x86.brillo.map
+++ b/libc/libc.x86.brillo.map
@@ -1257,6 +1257,7 @@
 LIBC_O {
   global:
     getdomainname;
+    hasmntopt;
     pthread_getname_np;
     setdomainname;
 } LIBC_N;