diff --git a/libc/arch-x86_64/bionic/__set_tls.c b/libc/arch-x86_64/bionic/__set_tls.c
index cc7a5f4..6845444 100644
--- a/libc/arch-x86_64/bionic/__set_tls.c
+++ b/libc/arch-x86_64/bionic/__set_tls.c
@@ -31,6 +31,6 @@
 
 extern int __arch_prctl(int, unsigned long);
 
-int __set_tls(void* ptr) {
+__LIBC_HIDDEN__ int __set_tls(void* ptr) {
   return __arch_prctl(ARCH_SET_FS, (uintptr_t) ptr);
 }