Function argument scoping bug
Don't import argument symtables in function prototypes
Allow basic addr-vs-int constant comparisons
Update struct-assert - disallow > lbl
Fix unary +/- constant folding
Handle offset-labels and label addressing
Need to do pointer stepping in both label and int const cases
Fix constant propagation of dereference

CONST_NEED_ADDR isn't const when dereferenced.
string-literals have their label created immediately
Const op folding doesn't swap lhs/rhs - keep commutativity
Rename "calcs" test directory
Constant initialiser errors aren't immediately fatal
Return CONST_NO for unary +/- on labels
The not operator returns a bool, e.g. !5.0 :: float -> bool
Constant address folding tests
Merge branch 'fix/const-expr-any-op'
Merge branch 'fix/funcarg-scope'