arm-nacl port

[Roland McGrath <roland at hack dot frob dot com>]

I'm now just about ready to commit the port to arm-nacl (better known as
Google Native Client on ARMv7-A machines).  I still have various issues to
work through, but it's reached the point where my continuing work will be
easier to do in the tree than out of it.

Is there anybody who actually wants to review the new code?

What I'd like to commit is currently sitting on the roland/nacl-merge
branch.  Aside from one line in abi-tags, it is entirely contained in new
sysdeps directories (sysdeps/arm/nacl, sysdeps/nacl) and thus clearly does
not affect any other configurations.

I'd certainly appreciate any detailed feedback anyone wants to give about
the implementation details.  But unless someone actively wants to review it
all (and quite soon), and if nobody objects for other reasons I can't think
of, then I'll just land it as is sometime this week.

Of course, once it's committed, future changes to the NaCl-specific files
will follow usual procedures for a port with a designated maintainer (I'll
post all changes and write proper ChangeLog entries, though not usually
wait for review before committing).

Note that I have not yet done things like README and NEWS changes, nor
.abilist files.  I expect to have everything stabilized before the next
release freeze, and will have those changes in by then.


Thanks,
Roland