[Bug other/122941] New: Backport r16-5492-g07a767c7a50d1d to release branches

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122941

            Bug ID: 122941
           Summary: Backport r16-5492-g07a767c7a50d1d to release branches
           Product: gcc
           Version: 15.2.1
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: schwab@linux-m68k.org
  Target Milestone: ---

If the host compiler defaults to C++23 then libcody cannot be compiled, causing
build failures when compiling a cross compiler from gcc < 16 sources.  The
toplevel configure only forces -std=c++14 when bootstrapping.