Libguestfs - Aug 2021 - [PATCH nbdkit v2 2/2] wrapper: Remove GLIBC_TUNABLES when running under valgrind

Thanks for the review.  This is what I pushed which I think should
incorporate all the suggestions you made.  I have also checked it
works with older glibc now.

https://gitlab.com/nbdkit/nbdkit/-/commit/362e0fdcae37db876e13b944102a5c152e6bc563
https://gitlab.com/nbdkit/nbdkit/-/commit/ae8c815e54e66ac7b421e0a6929c39d9ce3834dc

Rich.

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There's a problem here ...

For background see:
https://lists.fedoraproject.org/archives/list/devel at
lists.fedoraproject.org/thread/7R3H3RWXC2FEJ6MRTFFUZY5KRYKPL2TQ/
(You have to click the "..." in that email)

If libc_malloc_debug.so.0 isn't installed then LD_PRELOAD generates
lots of warning messages and this actually breaks some tests.

If ./configure is used without --libdir then we try to set
LD_PRELOAD=/usr/local/lib/libc_malloc_debug.so.0 which causes the
warnings/failures.

My first idea was to test in ./configure if $libdir/libc_malloc_debug.so.0
exists and only set LD_PRELOAD if so.  However that doesn't work
because of $!"?% exec_prefix (a.k.a. the most useless GNU feature that
no one uses but causes all the trouble).

Also if you have glibc.i686 and glibc.x86_64 installed then both
/lib64/libc_malloc_debug.so.0 and /lib/libc_malloc_debug.so.0 exist
and you must choose the correct one.  On other distros the path will
be different, eg. the 64 bit one in /lib/libc_malloc_debug.so.0 or
/lib/x86_64-linux-gnu/... etc.

So I don't know how to solve any of this.  It would be nicer if glibc
handled the details and automatically loaded the right library if
GLIBC_TUNABLES was set.

Rich.

-- 
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