[Bug libstdc++/119266] libstdc++.modules.json has wrong path

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119266

--- Comment #12 from Jason Merrill <jason at gcc dot gnu.org> ---
So if toolexeclibdir is /usr/lib64, how is modules.json ending up in
/usr/lib/gcc/x86_64-pc-linux-gnu/15/?  It's supposed to be in toolexeclibdir.