[config] silence failing mathl probes
[config] silence failing mathl probes

as e.g. with cygwin which has no lang math.
We are only interested in the result: yes, some or no,
and the PARROT_HAS_ defines in the generated has_header.h

tkob/parrot,parrot/parrot,youprofit/parrot,youprofit/parrot,parrot/parrot,youprofit/parrot,youprofit/parrot,parrot/parrot,tkob/parrot,tkob/parrot,tkob/parrot,tkob/parrot,tkob/parrot,tkob/parrot,parrot/parrot,youprofit/parrot,youprofit/parrot,youprofit/parrot,youprofit/parrot,parrot/parrot,tkob/parrot