https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103166
--- Comment #9 from Hans-Peter Nilsson <hp at gcc dot gnu.org> --- Elaboration: there may be (newlib) targets (build/test setups) where the test-setup can't link and thus erroneously gets a "yes" for these functions. If that happens for you, look into fixing newlib (like, providing a stub that returns -1 and sets errno=ENOSYS, which would work for libstdc++ as it has a fallback option - actually several fallback options). (Or, make newlib stop declaring functions it doesn't completely provide.) That was my plan B, thankfully GCC_TRY_COMPILE_OR_LINK did the right thing for my setup. :)
