https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90361
--- Comment #5 from Viktor Ostashevskyi <ostash at ostash dot kiev.ua> --- It would be nice at least document that for GCC 9.1.0 building with --with-default-libstdcxx-abi=gcc4-compatible is broken. Possible workaround is to build with default parameters and change _GLIBCXX_USE_DUAL_ABI define to 1 in bits/c++config.h after 'make install'.
