[PATCH] Revert r221183 to unbreak test-suite on OpenBSD / Bitrig

[Rafael Espíndola]

>> A  list of additional, user-specified, ELF shared libraries to be
>> loaded before all others.  The items of the list can be separated by
>> spaces or colons.
>>
>> so "" is just an empty list.
>
>
> "" is not valid. It is considered poor scripting.

Maybe the proper fix then is to replace

 environment[var] = os.environ.get(var, '')


with

val = os.environ.get(var, '')
if val != '':
  environment[var] = var

or whatever the canonical way of doing that in python is.

We should also have a comment saying why '' is explicitly avoided.

Cheers,
Rafael