This is interesting:

The PERL_DL_NONLAZY=1 mechanism was specifically designed to spot problems with unresolved symbols at _load_ time rather than leaving it till the symbol is possibly referenced later in the running code (causing a fatal error).

From an old P5P message here: http://www.gossamer-threads.com/lists/perl/porters/14482

I can't say why it matters here, but at least that's a description of what the environment variable does.