(gdb-var-evaluate-expression-handler)

(gdb-var-evaluate-expression-handler)
(gdb-var-update-handler): Detect out of scope variables with pre
GDB 6.4 too.
(gdb-post-prompt): Revert changet 2006-02-17 (force update).
Reset status of variable objexts to nil in update handlers.
(gdb-var-update-handler-1): Detect when a variable object comes
in scope.  setcar on var changes gdb-var-list directly.