This is a more complicated tracepoint fix.  The variable tracing mechanism
does not cope with COMPUTED_LOC and ARG_COMPUTED_LOC symbols, as generated
by gcc 3.4.  Expressions containing said symbols are dealt with.  This
patch rearranges 'collect_symbol' and 'add_local_symbols' to deal with
such computed symbols.  These are dumped as if they were expressions --
hence the breakout of the expression dumping from encode_actions.

built & tested on i686-pc-linux-gnu, and an unreleased remote
architecture. ok?

nathan

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Nathan Sidwell    ::   http://www.codesourcery.com   ::     CodeSourcery LLC
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