* apt-pkg/contrib/sha1.cc:

* apt-pkg/contrib/sha1.cc:
  - fix illegally casts of on-stack buffer to a type requiring more
    alignment than it has resulting in segfaults on sparc (Closes: #634696)

The problem is how sha1.cc codes the SHA1 transform, it illegally
casts the on-stack workspace buffer to a type requiring more
alignment than 'workspace' is actually declared to have.

This only shows up recently because gcc-4.6 now does a really
aggressive optimization where it gets rid of the workspace
buffer entirely and just accesses 'buffer' directly, and assumes
it has the necessary alignment for 32-bit loads (which it
doesn't).