https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87088
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
FWIW this was changed by r247222
2017-04-25 Bernd Edlinger
* c-common.c (c_type_hasher, type_hash_table): Remove.
(c_common_get_alias_set): Remove unreachable code.
* c-opts.c (c_common_post_options): Make sure cc1 takes only one file.
