First lexer tests, plus small trigraph bugfix

[Per Bothner]

Neil Booth <NeilB@earthling.net> writes:

> If anyone has good ideas on how to test whether a preprocessing number
> like "5.4.e+" is being treated as a single preprocessing token by the
> lexer, please let me know.  I can't think of a way to test this.

If you can't test it, I guess it doesn't matter?

Is there actually any reason we really need to worry about the concept
of "preprocessing number"?  Why not just have the integrated cpplib and
front-end-lexer just lex valid numbers?
- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/~per/