perl: fix static build

fix EUMM 7.04_01 which comes with Perl 5.22.0

with static lib build, we cannot call _find_magic_vstring(),

which does a `require B;` and B is not a pure Perl module.

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>

--- a/cpan/ExtUtils-MakeMaker/lib/ExtUtils/MakeMaker/version/vpp.pm

+++ b/cpan/ExtUtils-MakeMaker/lib/ExtUtils/MakeMaker/version/vpp.pm

@@ -933,7 +933,7 @@ sub _un_vstring {

     if ( length($value) >= 3 && $value !~ /[._]/

 	&& _is_non_alphanumeric($value)) {

 	my $tvalue;

-	if ( $] ge 5.008_001 ) {

+	if ( $Config{usedl} && ( $] ge 5.008_001 ) ) {

 	    $tvalue = _find_magic_vstring($value);

 	    $value = $tvalue if length $tvalue;

 	}