tests: Add dlopen override to dwfl-proc-attach for old glibc/valgrind.

Some combination of old glibc and valgrind create unsuppressable memory
leak warnings when the process is run under valgrind, is multi-threaded
and uses dlopen. libdw will try to dlopen libdebuginfod be default.
So simply override dlopen and always return NULL to make sure
libdebuginfod is never loaded.  The dwfl-proc-attach test doesn't rely
on libdebuginfod anyway.

This was seen on the armbian buildbot which uses valgrind 3.14.0 and
glibc 2.28.

Signed-off-by: Mark Wielaard <mark@klomp.org>
2 files changed