[Bug libstdc++/101867] avr libc build error for libstdc++

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101867

--- Comment #16 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
--with-avrlibc is default, so setting it is void. C.f. install info.