diff --git a/libc/stdio/local.h b/libc/stdio/local.h
index 7afa761..7ab73c0 100644
--- a/libc/stdio/local.h
+++ b/libc/stdio/local.h
@@ -41,6 +41,8 @@
 #include "wcio.h"
 #include "fileext.h"
 
+#pragma GCC visibility push(hidden)
+
 int	__sflush(FILE *);
 int	__sflush_locked(FILE *);
 FILE	*__sfp(void);
@@ -118,3 +120,10 @@
     return (__swbuf(_c, _p));
   }
 }
+
+/* OpenBSD declares these in fvwrite.h but we want to ensure they're hidden. */
+struct __suio;
+extern int __sfvwrite(FILE *, struct __suio *);
+wint_t __fputwc_unlock(wchar_t wc, FILE *fp);
+
+#pragma GCC visibility pop