https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84829
--- Comment #12 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- Programs linked with glibc 2.26 will continue to work as expected. _LIB_VERSION has become a compat symbol, so it's newly linked programs that can't set it any more (and in static libm, and libm for new ports such as RISC-V, all the code relating to _LIB_VERSION and matherr is completely gone). To use matherr with old glibc you needed to set _LIB_VERSION to _SVID_ (default is _POSIX_, libieee.a set it to _IEEE_, the difference between _POSIX_ and _IEEE_ is that _IEEE_ disables errno setting for *some* functions, not all).
