[tpm] Dependency chains

[arocker at vex.net]

Is there any way to check the dependency chain of a CPAN module against an
installed configuration in advance of an attempt to install?

It would be so much more agreeable to start from the bottom and work
upwards, in a series of successes, than to work down through a succession
of aborts and then back up, (especially when some of the dependencies
appear to be mutual).