Flatten sysdeps/unix/bsd/bsd4.4 into sysdeps/unix/bsd.

Flatten sysdeps/unix/bsd/bsd4.4 into sysdeps/unix/bsd.

As discussed in
<https://sourceware.org/ml/libc-alpha/2012-04/msg00840.html> and
<https://sourceware.org/ml/libc-alpha/2012-04/msg00989.html>, it seems
appropriate to flatten sysdeps/unix/bsd/bsd4.4 into sysdeps/unix/bsd.

The bulk of the patch is just moving files.  The only other changes
are: update paths in sysdeps/mach/hurd/Implies and
sysdeps/unix/sysv/linux/wait3.c; merge the two syscalls.list files,
with the removal of syscalls that were in
sysdeps/unix/bsd/syscalls.list but overridden in the bsd4.4 directory
by .c files there.

Tested x86_64.  The installed shared libraries are identical before
and after the patch except for libc.so where the move of wait3.c
(included by sysdeps/unix/sysv/linux/wait3.c) affects debug info, but
the disassembly is unchanged.

	* sysdeps/mach/hurd/Implies: Change unix/bsd/bsd4.4 to unix/bsd.
	* sysdeps/unix/bsd/syscalls.list (chflags): Add entry from
	sysdeps/unix/bsd/bsd4.4/syscalls.list.
	(fchflags): Likewise.
	(revoke): Likewise.
	(setlogin): Likewise.
	(sigaltstack): Likewise.
	(wait4): Likewise.
	(sigblock): Remove.
	(sigsetmask): Likewise.
	(wait3): Likewise.
	(waitpid): Likewise.
	* sysdeps/unix/bsd/bsd4.4/syscalls.list: Remove file.
	* sysdeps/unix/sysv/linux/wait3.c: Update directory of included
	file.
	* sysdeps/unix/bsd/bsd4.4/Makefile: Move to ...
	* sysdeps/unix/bsd/Makefile: ... here.
	* sysdeps/unix/bsd/bsd4.4/Versions: Move to ...
	* sysdeps/unix/bsd/Versions: ... here.
	* sysdeps/unix/bsd/bsd4.4/bits/sockaddr.h: Move to ...
	* sysdeps/unix/bsd/bits/sockaddr.h: ... here.
	* sysdeps/unix/bsd/bsd4.4/cmsg_nxthdr.c: Move to ...
	* sysdeps/unix/bsd/cmsg_nxthdr.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/sigblock.c: Move to ...
	* sysdeps/unix/bsd/sigblock.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/sigsetmask.c: Move to ...
	* sysdeps/unix/bsd/sigsetmask.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/sigvec.c: Move to ...
	* sysdeps/unix/bsd/sigvec.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/tcdrain.c: Move to ...
	* sysdeps/unix/bsd/tcdrain.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/tcgetattr.c: Move to ...
	* sysdeps/unix/bsd/tcgetattr.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/tcsetattr.c: Move to ...
	* sysdeps/unix/bsd/tcsetattr.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/wait.c: Move to ...
	* sysdeps/unix/bsd/wait.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/wait3.c: Move to ...
	* sysdeps/unix/bsd/wait3.c: ... here.
	* sysdeps/unix/bsd/bsd4.4/waitpid.c: Move to ...
	* sysdeps/unix/bsd/waitpid.c: ... here.