It used to be that the FreeBSD port of Valgrind couldn't work with the system Perl, but that was because the FreeBSD system Perl was built with -Dusemymalloc, which Valgrind can't handle. I don't know of a similar problem with any system Perl in a Linux distro, nor have I seen any problems with a system Perl on OS X. Valgrind works with Perl on all those systems. It also works with Perl on FreeBSD if you custom compile your own Perl without -Dusemymalloc.

The only Configure prompts I know of relating to malloc() control PERL_MALLOC_WRAP and usemymalloc:

Do you wish to wrap malloc calls to protect against potential overflow
+s? [y] n
 
Do you wish to attempt to use the malloc that comes with perl5? [n]
[download]

If we want to work with Valgrind, we definitely don't want to enable usemymalloc (which is disabled by default).

The Accflags="-DNO_FANCY_MALLOC -DPLAIN_MALLOC " Configure flag worked as intended -- thanks for the tip! Unfortunately, it did not produce a Perl that allowed us to use Valgrind in place of Test::LeakTrace.

Maybe what we want is impossible because of how the global destruction phase works in Perl. If we use a debugging Perl and set PERL_DESTRUCT_LEVEL to 2, Perl will clean up all scalars, regardless of their refcounts. If we don't set PERL_DESTRUCT_LEVEL, it drops everything on the floor and lets the process exit() clean things up. There's no middle ground where it leaves only scalars with leaked refcounts behind.