MSVC: allow using ExtUtils::MakeMaker

Drop NO_PERL_MAKEMAKER from config.mak.uname for the MSVC platform.

MakeMaker is available on Windows Perl implementations and
installs modules to correct location, unlike NO_PERL_MAKEMAKER Makefile.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>