[Bug c/105688] Cannot build GCC 11.3 on Fedora 36

[aros at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105688

--- Comment #2 from Artem S. Tashkinov <aros at gmx dot com> ---
This workaround of mine is not really good: after `make install` you end up
with /opt/gcc/lib64/libstdc++.so.6.0.29 which is not GCC's but the system one
(/usr/lib64/libstdc++.so.6.0.30.so).