pgsql: Document which versions of ActivePerl and ActiveTcl are required

Log Message:
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Document which versions of ActivePerl and ActiveTcl are required
for building on MSVC, and that the free distribution is enough
(no need for the enterprise version).

Per gripe from Martin Zaun.

Modified Files:
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pgsql/doc/src/sgml:
install-win32.sgml (r1.47 -> r1.48)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/install-win32.sgml?r1=1.47&r2=1.48)