widl: The lval member of var_t is essentially a duplicate of eval->cval.

- Generate eval's for enums that don't explicitly have one. This means
that enums written in header files won't match exactly what has been put
into the IDL file, but the numeric constat is the same and MIDL does a
similar thing.
- Replace constant lookups with eval->cval instead of lval.
3 files changed