diff --git a/libc/stdio/flockfile.c b/libc/stdio/flockfile.c
index bfb081c..e8c74c5 100644
--- a/libc/stdio/flockfile.c
+++ b/libc/stdio/flockfile.c
@@ -191,7 +191,7 @@
 
 
 /* called from fclose() to remove the file lock */
-void
+__LIBC_HIDDEN__ void
 __fremovelock(FILE*  fp)
 {
     LockTable*  t = lock_table_lock();