bugfix: proper message locking on message destruct

It looks like a race was introduced by not locking the message mutex
in msgDestruct(). In theory, I thought, the decrement should be atomic,
but the whole operation may be reordered. Also it has potential for task
switches. If so, that would lead to a too-early destruction and thus
a potential double free - exactly what we have seen from time to time.
So I think this fix addresses the issue.

I have also removed anything that looks like atomic operations are supported
in this version - they are not. This was very late added, found to be
non-portable and pulled from that release.

0 files changed, 0 insertions, 0 deletions