Here is the new fixed patch. The following operators are covered:

A large number of operators in the evaluate_subexp_standard function
are not changed as I am unsure what they are used for or not sure
about the correct way to change them.

In a sense it depends on whether it should be possible to check the
scope of complex expressions. I think it probably should, as it is
consistent, but it would require extra work to implement and may not
be worth it as people may never use it.

However, currently it should be possible to check if variables,
constants, structures and memebers of structures/classes are in scope.

For binary operators, I consider that an expresion is on scope of all
of it's sub expressions are in scope, that is a binary AND. This is
implemented (trivially) for the case for AND, and also for the case
for OR. I wanted to check that we way I had done ti was teh best way
to do it, before I added a case to every other binary operator.

For unary operators, the value should just be the value of the
subexpression (currently this is unimplemented, but will be when I can
face the monotony of a lot of cutting and pasting).

Any thoughts you have on the patch, other cases which should be
covered, better ways of doing it, test cases, and anything like that
is much appreciated.

Thanks,
Rob

P.S. There still seems to be a lot of extra info in the diff, despite
now having build directories sorted properly.