Move __cxa_thread_atexit* to its own .c file to avoid pulling the code
(w/ _dlctl reference) into static executables. It's all Mark's code so
put his preferred copyright on it.

ok kettenis@

Implement __cxa_thread_atexit to support C++11 thread_local scope. The
interface is also made available as __cxa_thread_atexit_impl to satisfy the
needs of GNU libstdc++.

ok guenther@, millert@

Hide __atexit and __atexit_register_cleanup()
Wrap __cxa_{atexit,finalize}() so the call from exit() goes direct
Switch regress/lib/libc/atexit/ to be built with -static so that it can
still access __atexit*

ok millert@ jca@

Always call atexit handlers as if they were registered with __cxa_atexit.
The extra argument doesn't hurt genuine atexit handlers and this fixes a
bug where we didn't provide the argument (effectively passing garbage) for
functions registered with __cxa_atexit in the main executable.

Pointed out by Dmitriy Ivanov <dimitry@google.com> and Elliott Hughes
<enh@google.com>.

ok matthew@

Two small cleanups to atexit: remove unneeded __atexit_invalid, and
move the call_depth decrement so it happens unconditionally and can
still return to 0 when called with dso!=NULL.

ok millert

Add __cxa_atexit() support for gcc3. This provides support for shared object destructors called at dlclose() time. Inspired by similar changes in FreeBSD and NetBSD.

fix a proto

re-enable function pointer table protection, this time make sure that
malloc.c gets the first mmap() call (since it depends on that, for its
sbrk(0) use). ok deraadt@

Back it out, it breaks something in perl (seen with spamassassin), debug
first.

Replace atexit handler. mprotect() the pages so an attempt to modify the
function pointers from the outside will segfault. Idea, hints and feedback
from deraadt. ok deraadt.

Fix RCS ids
Make sure everything uses {SYS,}LIBC_SCCS properly

branches: 1.1.1;
Initial revision