diff --git a/libc/arch-x86/syscalls/munlock.S b/libc/arch-x86/syscalls/munlock.S
index 2fc3aa7..6b79e99 100644
--- a/libc/arch-x86/syscalls/munlock.S
+++ b/libc/arch-x86/syscalls/munlock.S
@@ -2,6 +2,8 @@
 
 #include <private/bionic_asm.h>
 
+    .hidden __set_errno
+
 ENTRY(munlock)
     pushl   %ebx
     .cfi_def_cfa_offset 8