[SCons] Optionally show contents of config.log after errors
[SCons] Optionally show contents of config.log after errors

This makes it easier to debug issues that occur on automated builds where
the config.log file is hard to access directly.

imitrichev/cantera,imitrichev/cantera,imitrichev/cantera,imitrichev/cantera,imitrichev/cantera,imitrichev/cantera