[Bug c/84953] misleading warning from strpbrk(x,"")

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84953

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 43710
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43710&action=edit
gcc8-pr84953.patch

Untested fix.