- partially addresses #1209 and #1187
- only query 64-bit extension on seeing use of a 64-bit literal
(was doing it for every single token)
- correct HLSL acceptance of 64-bit literal syntax (still an int though)
- error on overflow of 32-bit literal type
When preprocessing only, some tokens were emitted as <bad token>.
This fixes them to preserve their original content.
This supplants PR #182, with a correction and test results.
