https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85672
--- Comment #13 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Tue May 8 13:05:04 2018 New Revision: 260043 URL: https://gcc.gnu.org/viewcvs?rev=260043&root=gcc&view=rev Log: PR libstdc++/85672 #undef _GLIBCXX_USE_FLOAT128 when not supported Restore the behaviour in GCC 8 and earlier where _GLIBCXX_USE_FLOAT128 is not defined when configure detects support is missing. This avoids having three states where the macro is either 1, 0, or undefined. PR libstdc++/85672 * include/Makefile.am [!ENABLE_FLOAT128]: Change c++config.h entry to #undef _GLIBCXX_USE_FLOAT128 instead of defining it to zero. * include/Makefile.in: Regenerate. * include/bits/c++config (_GLIBCXX_USE_FLOAT128): Move definition within conditional block. Modified: trunk/libstdc++-v3/ChangeLog trunk/libstdc++-v3/include/Makefile.am trunk/libstdc++-v3/include/Makefile.in trunk/libstdc++-v3/include/bits/c++config
