[Bug sanitizer/117731] [15 Regression] libsanitizer builds not as c++17 even though it uses c++17 features

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117731

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 59668
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59668&action=edit
gcc15-pr117731.patch

Untested fix.