minor bug in automake

[Greg Lindahl]

The AC_LIBTOOL_PROF_CC_C_O rule in aclocal.m4 generated by Automake
has the comment:

# The compiler can only warn and ignore the option if not recognized
# So say no if there are any warnings

This isn't very smart -- let's say that the user has specified CFLAGS
that generate a warning with every compile. Then this test will appear
to fail.

I noticed because I was diffing config.out for configs run with
various compilers... the package I was using doesn't actually use the
results of this rule.

-- greg