And add extra checks to enable for binutils 2.45 and if the architecture
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>

Enable SFrame stack track information. The --enable-sframe option
allows the glibc build to compile with SFrame stack track
information. Thus, enabling glibc's backtrace to work within glibc.

Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
Reviewed-by: Sam James <sam@gentoo.org>

When GNU Binutils is configured with --enable-error-execstack=yes, a handful
of our tests which rely on -Wl,-z,execstack fail. Pass --Wl,--no-error-execstack
to override the behaviour and get a warning instead.

Bug: https://sourceware.org/PR32717
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

The purpose of this patch is to add some system calls that (1) aren't
otherwise documented, and (2) are merely redirected to the kernel, so
can refer to their documentation; and define a standard way of doing
so in the future.  A more detailed explaination of how system calls
are wrapped is added along with reference to the Linux Man-Pages
project.

Default version of man-pages is in configure.ac but can be overridden
by --with-man-pages=X.Y

Reviewed-by: Alejandro Colomar <alx@kernel.org>

All the crypt related functions, cryptographic algorithms, and
make requirements are removed,  with only the exception of md5
implementation which is moved to locale folder since it is
required by localedef for integrity protection (libc's
locale-reading code does not check these, but localedef does
generate them).

Besides thec code itself, both internal documentation and the
manual is also adjusted.  This allows to remove both --enable-crypt
and --enable-nss-crypt configure options.

Checked with a build for all affected ABIs.

Co-authored-by: Zack Weinberg <zack@owlfolio.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

The option is not activelly tested and has bitrotten, to fix it
would require a lot of work and multiple fixes.  A better option
would to evaluate each option and enable the warning if it makes
sense.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

Add --enable-fortify-source option.

It is now possible to enable fortification through a configure option.
The level may be given as parameter, if none is provided, the configure
script will determine what is the highest level possible that can be set
considering GCC built-ins availability and set it.
If level is explicitly set to 3, configure checks if the compiler
supports the built-in function necessary for it or raise an error if it
isn't.

If the configure option isn't explicitly enabled, it _FORTIFY_SOURCE is
forcibly undefined (and therefore disabled).

The result of the configure checks are new variables, ${fortify_source}
and ${no_fortify_source} that can be used to appropriately populate
CFLAGS.

A dedicated patch will follow to make use of this variable in Makefiles
when necessary.

Updated NEWS and INSTALL.

Adding dedicated x86_64 variant that enables the configuration.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

And make always supported.  The configure option was added on glibc 2.25
and some features require it (such as hwcap mask, huge pages support, and
lock elisition tuning).  It also simplifies the build permutations.

Changes from v1:
 * Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs
   more discussion.
 * Cleanup more code.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

It is the default since 2.26 and it has bitrotten over the years,
By using it multiple malloc tests fails:

  FAIL: malloc/tst-memalign-2
  FAIL: malloc/tst-memalign-2-malloc-hugetlb1
  FAIL: malloc/tst-memalign-2-malloc-hugetlb2
  FAIL: malloc/tst-memalign-2-mcheck
  FAIL: malloc/tst-mxfast-malloc-hugetlb1
  FAIL: malloc/tst-mxfast-malloc-hugetlb2
  FAIL: malloc/tst-tcfree2
  FAIL: malloc/tst-tcfree2-malloc-hugetlb1
  FAIL: malloc/tst-tcfree2-malloc-hugetlb2

Checked on x86_64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>

Now that there is no need to use a special linker script to hardening
internal data structures, remove the --with-default-link configure
option and associated definitions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>