[Bug preprocessor/79210] "internal compiler error: in get_substring_ranges_for_loc" processing -Wformat-signedness warning

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79210

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
input.c:1398 is:

      gcc_assert (line_width >= (start.column - 1 + literal_length));

which was the one failing in PR 78569.

Could be due to a different root cause, though; I'll take a look.