best way to check for compiler _warnings_?

[Miles Bader]

I want to check whether the compiler is giving a warning (about an
unrecognized command-line option).

Since the compilation still succeeds, AC_COMPILE_IFELSE doesn't do the
job...

e.g.:

   $ g++ -o /dev/null -catfood -c /tmp/s.cc ; echo $?
   g++: unrecognized option '-catfood'
   0
   $ 

argh

Thanks,

-miles


-- 
Abstainer, n. A weak person who yields to the temptation of denying himself a
pleasure. A total abstainer is one who abstains from everything but
abstention, and especially from inactivity in the affairs of others.