malloc.conf on BeagleBone Black

[hans]

I started using the wonderfull malloc.conf,
setting it to CFGJPRSU. This works on amd64 and macppc and i386,
but on a freshly upgraded current/armv7 (a BeagleBone Black),
some programs report

        malloc() warning: unknown char in MALLOC_OPTIONS

Each of the flags is documented in the malloc.conf(5) manpage.
Is there something specific about this on the BBB?

        Jan