[Bug c/77336] -Wsuggest-attribute=format warning overly simplistic

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77336

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Created attachment 39488
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39488&action=edit
Prototype patch.

Attached a lightly tested patch.