--- Libc/Libc-825.26/stdlib/FreeBSD/exit.c
+++ Libc/Libc-763.13/stdlib/FreeBSD/exit.c
@@ -42,7 +42,15 @@
 #include "libc_private.h"
 
 void (*__cleanup)(void);
-extern void __exit(int);
+
+/*
+ * This variable is zero until a process has created a thread.
+ * It is used to avoid calling locking functions in libc when they
+ * are not required. By default, libc is intended to be(come)
+ * thread-safe, but without a (significant) penalty to non-threaded
+ * processes.
+ */
+int	__isthreaded	= 0;
 
 /*
  * Exit, flushing stdio buffers if necessary.
@@ -51,8 +59,13 @@
 exit(status)
 	int status;
 {
+	/* Ensure that the auto-initialization routine is linked in: */
+	extern int _thread_autoinit_dummy_decl;
+
+	_thread_autoinit_dummy_decl = 1;
+
 	__cxa_finalize(NULL);
 	if (__cleanup)
 		(*__cleanup)();
-	__exit(status);
+	_exit(status);
 }