configure: add prefix to err messages in has_or_{abort,warn}

Make it easier to spot messages spewed out by has_or_{abort,warn}.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="Harold Grovesteen"

 reporter_url="http://sourceware.org/ml/crossgcc/2009-11/msg00052.html"

 reporter_comment=""