[Bug c++/124806] Segfault in elf_out::end() when no mmap support

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124806

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Torbjorn Svensson
<[email protected]>:

https://gcc.gnu.org/g:996979360a4027c1e85770cde031e673f8288e9d

commit r15-11466-g996979360a4027c1e85770cde031e673f8288e9d
Author: Torbjörn SVENSSON <[email protected]>
Date:   Sun Jul 26 23:25:50 2026 +0200

    c++: ICE on on systems without mmap support [PR124806]

    On systems without mmap support, cc1plus can crash when finishing module
    output after earlier errors prevented elf_out::begin from running.  In
    that case elf_out::end attempts to fill in the ELF header even though
    hdr.buffer was never initialized.

    gcc/cp/ChangeLog:

            PR c++/124806
            * module.cc (elf_out::began): New data member.
            (elf_out::begin): Set it after successful initialization.
            (elf_out::end): Do not finalize output that never began.

    Signed-off-by: Torbjörn SVENSSON <[email protected]>
    (cherry picked from commit 94556938452d2bde01f5954207294906bbb53d8f)