[PATCH v2 1/2] Disable SFrame support by default

[Sam James]

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:

> And add extra checks to enable for binutils 2.45 and if the archicture
> explicitly enables it.  When SFrame is disabled, all the related code
> is also not enabled for backtrace() and _dl_find_object(), so SFrame
> backtracking is not used even if the binary has the SFrame segment.
>
> This patch also adds some other related fixes:
>
>   * Fixed an issue with AC_CHECK_PROG_VER, where the READELF_SFRAME
>     usage prevented specifying a different readelf through READELF
>     environment variable at configure time.
>
>   * Add an extra arch-specific internal definition,
>     libc_cv_support_sframe, to disable --enable-sframe on architectures
>     that have binutils but not glibc support (s390x).
>
>   * Renamed the tests without the .sframe segment and move the
>     tst-backtrace1 from pthread to debug.
>
>   * Use the built compiler strip to remove the .sframe segment,
>     instead of the system one (which might not support SFrame).
>
> Checked on x86_64-linux-gnu and aarch64-linux-gnu.

Reviewed-by: Sam James <sam@gentoo.org>