> Hmmm ... perhaps Ruby/Windows is stripping off or not
> stripping off an end-of-line character inappropriately?

I had the same problem a couple of weeks ago.

Use plain Windows, no Ruby, and you get the same kind of
results. It's just not possible to set an environment variable
to an empty string, on Windows.

gegroet,
Erik V. - http://www.erikveen.dds.nl/

----------------------------------------------------------------

 H:\> set FOO=bar

 H:\> echo %FOO%
 bar

 H:\> set FOO=

 H:\> echo %FOO%
 %FOO%

 H:\> set FOO=''

 H:\> echo %FOO%
 ''

 H:\> set FOO=""

 H:\> echo %FOO%
 ""

----------------------------------------------------------------