pa_memblock is now an opaque structure. Access to its fields is now done
through various accessor functions in a thread-safe manner.
pa_memblock_acquire() and pa_memblock_release() are now used to access the
attached audio data. Why? To allow safe manipulation of the memory pointer
maintained by the memory block. Internally _acquire() and _release() maintain a
reference counter. Please do not confuse this reference counter whith the one
maintained by pa_memblock_ref()/_unref()!
As a side effect this patch removes all direct usages of AO_t and replaces it
with pa_atomic_xxx based code.
This stuff needs some serious testing love. Especially if threads are actively
used.
git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1404 fefdeb5f-60dc-0310-8127-8f9354f1896f
