Addition of EBCDIC support to safe-ctype.c and hex.c in libiberty

[DJ Delorie]

> Bootstrapping and testing: Compiled on OS/390 V2R10 (native) and
> RedHat 7.2 Intel (cross-compile).
> 
> Patch: Attached.

It doesn't apply to current sources (hex.c has changed).  Could you
please update it?

Oh, and you technically shouldn't need the hex.c patch any more,
although gcc doesn't follow the rules and call hex_init().  Still good
to have it, though.