[gfortran] Fix PR 16579: Signed/Unsigned confusion in ICHAR

[Paul Brook]

> 2004-08-31  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
>
>  PR fortran/16579
>  * trans-types.c (gfc_init_types): Make gfc_character1_type_node an
>  unsigned char.

Ok.

Paul