NOTES.WIN: mention Strawberry Perl as option.

Reviewed-by: Rich Salz <rsalz@openssl.org>

NOTES.WIN

diff --git a/NOTES.WIN b/NOTES.WIN
index 2a3c1e1..c31aed9 100644
--- a/NOTES.WIN
+++ b/NOTES.WIN
@@ -9,7 +9,8 @@
  this are required as well:
 
  - You need Perl.  We recommend ActiveState Perl, available from
-   https://www.activestate.com/ActivePerl.
+   https://www.activestate.com/ActivePerl. Another viable alternative
+   appears to be Strawberry Perl, http://strawberryperl.com.
    You also need the perl module Text::Template, available on CPAN.
    Please read NOTES.PERL for more information.