blocker: $ENV{foo} = undef

5.17.3 introduced changes to assignment to values in %ENV.  For one thing,
values are stringified immediately.  This has been discussed, and should stay.

For another thing, assigning undef to an entry in %ENV deletes the entry.  This
has been discussed, and should be reverted.  The original patch author agrees,
but we still have no reversion.

This is a blocker.

  https://rt.perl.org/rt3/Ticket/Display.html?id=114504

Patch needed.

-- 
rjbs

• blocker: $ENV{foo} = undef by Ricardo Signes