proposal: remove traditional C support from lint

Hi,

when I run lint with the -t flag for traditional C (which means before
C90), I always get these warnings:

$ >empty.c
$ lint -t empty.c
(1): warning: 'long double' is illegal in traditional C [266]
(1): warning: function prototypes are illegal in traditional C [270]
(2): warning: 'long double' is illegal in traditional C [266]
(2): warning: function prototypes are illegal in traditional C [270]
(3): warning: 'long double' is illegal in traditional C [266]
(3): warning: 'long double' is illegal in traditional C [266]
(3): warning: function prototypes are illegal in traditional C [270]

These warnings are generated by the following 3 declarations that have
been built-in into lint since main1.c 1.22 from 2014:

     int __builtin_isinf(long double);
     int __builtin_isnan(long double);
     int __builtin_copysign(long double, long double);

I don't know of anyone having complained about these obviously bogus
warnings, therefore I suspect that nobody is using the -t flag anymore,
which makes sense to me, given that traditional C has been superseded by
C90 over 30 years ago.

Any objections to removing the -t flag and everything that belongs to it?

Roland