Update.

Update.

	* Makefile: Add rules to build and run tst-atfork2 test.
	* tst-atfork2.c: New file.
	* tst-atfork2mod.c: New file.

	* sysdeps/unix/sysv/linux/unregister-atfork.c
	(__unregister_atfork): Free the memory allocated for the handlers
	after removing them from the lists.

	* sysdeps/unix/sysv/linux/register-atfork.c: Define memeory
	cleanup function.

	* tst-atfork1.c (do_test): Wait for the child we forked.
	Report error in child.

	* sysdeps/unix/sysv/linux/fork.c (__libc_fork): Fix comment.