[tz] [PROPOSED] Remove old Y2K code

[Jonathan Lennox]

On Monday, June 12 2017, "Paul Eggert" wrote to "Brian.Inglis at SystematicSw.ab.ca, Time zone mailing list" saying:

> Perhaps you're right, I was too hasty. I brought back that code under 
> the name you suggested, by installing the attached.


> +    Y2K runtime checks are no longer enabled by default.  Add
> +    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
> +    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
> +    to disable them.  (New name suggested by Brian Inglis.)
> +

Since DEPRECATE_TWO_DIGIT_YEARS is used in an if statement, shouldn't this
be -DDEPRECATE_TWO_DIGIT_YEARS=true ?  Otherwise it expands to
    if ( && warn != IN_NONE ...

which obviously won't compile.

-- 
Jonathan Lennox
lennox at cs.columbia.edu