Merge from vendor branch TNF:

Merge from vendor branch TNF:
Initial import of p5-Dist-CheckConflicts-0.02:

One shortcoming of the CPAN clients that currently exist is that
they have no way of specifying conflicting downstream dependencies
of modules. This module attempts to work around this issue by
allowing you to specify conflicting versions of modules separately,
and deal with them after the module is done installing.