[PATCH] glibc: Support scanning for aligned chunks.

[Carlos O'Donell]

Florian, DJ,

I have tested DJ's aligned chunk scanning code in Fedora Rawhide by doing a 
full toolchain bootstrap and looking for problems. I found no issues and
didn't see any regressions in either glibc or gcc's testsuites.

I am fairly confident that the code works and doesn't cause serious problems,
but I'd like a double check from both of you.

I have pushed the commit to Fedora Rawhide so you can view it there, but
I haven't issued a Rawhide build yet.

-- 
Cheers,
Carlos.