Merged revisions 88805 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

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r88805 | russell | 2007-11-05 16:07:54 -0600 (Mon, 05 Nov 2007) | 12 lines

After seeing crashes related to channel variables, I went looking around at the
ways that channel variables are handled.  In general, they were not handled in
a thread-safe way.  The channel _must_ be locked when reading or writing from/to
the channel variable list.

What I have done to improve this situation is to make pbx_builtin_setvar_helper()
and friends lock the channel when doing their thing.  Asterisk API calls almost 
all lock the channel for you as necessary, but this family of functions did not.

(closes issue #10923, reported by atis)
(closes issue #11159, reported by 850t)

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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@88934 65c4cc65-6c06-0410-ace0-fbb531ad65f3