[Bug c++/126309] New: [CWG3020] __has_cpp_attribute(indeterminate) should be nonzero with -std=c++26

[rs2740 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126309

            Bug ID: 126309
           Summary: [CWG3020] __has_cpp_attribute(indeterminate) should be
                    nonzero with -std=c++26
           Product: gcc
           Version: 16.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rs2740 at gmail dot com
  Target Milestone: ---

PR 114457 added support for the attribute but doesn't seem to have defined the
feature test macro, which was added by
https://cplusplus.github.io/CWG/issues/3020.html