diff --git a/libc/arch-x86_64/syscalls/prctl.S b/libc/arch-x86_64/syscalls/prctl.S
index c79220d..b4cdaa5 100644
--- a/libc/arch-x86_64/syscalls/prctl.S
+++ b/libc/arch-x86_64/syscalls/prctl.S
@@ -2,6 +2,8 @@
 
 #include <private/bionic_asm.h>
 
+    .hidden __set_errno
+
 ENTRY(prctl)
     movq    %rcx, %r10
     movl    $__NR_prctl, %eax