[tex-live] external perl on win32

[T T]

On 15 December 2010 12:35, T T <t34www at googlemail.com> wrote:
> We plan to introduce an explicit option to enable search for an
> external Perl with a default value set to disabled.

I just committed the above change---an external Perl will be now used
only if variable

  TEXLIVE_WINDOWS_TRY_EXTERNAL_PERL=1

is explicitly set (in texmf.cnf or environment).

In the process, all Perl programs shipped with TL got tested and apart
from one they all seem to work, so an external Perl should be rarely
needed in practice.

Cheers,

Tomek