Re: [PATCH v3] test-lib.sh: Use GLIBC_TUNABLES instead of MALLOC_CHECK_ on glibc >= 2.34

> In glibc >= 2.34 MALLOC_CHECK_ and MALLOC_PERTURB_ environment
> variables have been replaced by GLIBC_TUNABLES.  Also the new
> glibc requires that you preload a library called libc_malloc_debug.so
> to get these features.
>
> Using the ordinary glibc system variable detect if this is glibc >= 2.34 and
> use GLIBC_TUNABLES and the new library.
>
> This patch was inspired by a Richard W.M. Jones ndbkit patch
>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
> ---
> This is the third version of the patch.
>
> Compared to the second version[1], the code is further simplified,
> eliminating a case statement and modifying a string statement.