diff --git a/port/moonlight/src/bootup.c b/port/moonlight/src/bootup.c
index 4c1c61f..af34dcd 100644
--- a/port/moonlight/src/bootup.c
+++ b/port/moonlight/src/bootup.c
@@ -55,6 +55,10 @@ EXTERN_C void _exit(int exit_code) __attribute__ ((noreturn,noinline,weak));
 // Standard entry point, no arguments.
 extern int main(void);
 
+#ifdef __THREAD_LOCAL_STORAGE
+EXTERN_C void _set_tls(uint8_t*) __attribute__ ((noreturn,section(".text.boot")));
+#endif
+
 #if defined BOOTUP_SMP_ENABLED
 EXTERN_C void _secondary_initialize(void) __attribute__ ((noreturn,section(".text.boot")));
 EXTERN_C void _secondary_ipi_trap(void) __attribute__ ((naked,noreturn,section(".text.boot")));