Package and Environment Details

• Package Name/Version: gsl-lite/0.38.1

The version of the conanfile.py in this repo differs quite drastically from the upstream version, specifically we found that we can't use the conan-center version because it requires a user to choose a contract violation behavior upfront whereas the upstream version does not. Our build system needs to be able to decide the violation policy for itself at a later stage because we reuse conan dependencies for all submodules and some submodules require a different violation policy from the rest.

I propose we add None to the list of valid values for the on_contract_violation option and make it so that conanfile.py doesn't add any defines when on_contract_violation is None.