[gfortran,patch] Add MIN/MAX for character type

[FX Coudert]

> There should be errors/warnings for this feature, as for the others
> F2003 features, for -std=f95.
>
> OK if you add that.

Committed as rev. 127252 after adding the standard-check and  
regtesting on x86_64-linux: http://gcc.gnu.org/ml/gcc-cvs/2007-08/ 
msg00144.html

Thanks for the review,
FX