Report configured port in MSVC built pg_config

This is a long standing omission, discovered when trying to write code
that relied on it.

Backpatch to all live branches.

src/tools/msvc/Solution.pm

@@ -1198,6 +1198,8 @@ sub GetFakeConfigure
 	$cfg .= ' --with-tcl'           if ($self->{options}->{tcl});
 	$cfg .= ' --with-perl'          if ($self->{options}->{perl});
 	$cfg .= ' --with-python'        if ($self->{options}->{python});
+	my $port = $self->{options}->{'--with-pgport'};
+	$cfg .= " --with-pgport=$port" if defined($port)
 
 	return $cfg;
 }