Provide all config vars to test probes systematically

Generate a list of compiler options that does the defines in the same
manner that it would for config.h
Only write message if operation actually performed

Wording of the message was so that one could believe that a libtool
archive had been written even though it had not.
Merge pull request #157 from rolk/157_confopts

Provide a similar list of options to probes as is given to code