[Bug c/46635] c-family/c-common.c uses BITS_PER_UNIT in lieu of TYPE_PRECISION (char_type_node)

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46635

--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Jorn Wolfgang Rennecke from comment #1)
> As Joseph S. Myers bentioned in comment 1 of PR46633, 

(this is the last bug open blocking that one, btw)