Use XML::SAX::ExpatXS if available

Build.PL

@@ -26,7 +26,7 @@ my $build = Module::Build->new(
     recommends     => {
         'Growl::GNTP' => '0.15',
         'Net::DBus'   => '0',
-        'XML::SAX'    => '0',
+        'XML::SAX::ExpatXS' => '0',
         'Wx'          => '0.9901',
     },
     script_files    => ['slic3r.pl'],

lib/Slic3r/Format/AMF.pm

@@ -7,14 +7,17 @@ sub read_file {
     my $self = shift;
     my ($file) = @_;
     
-    eval "require Slic3r::Format::AMF::Parser; 1"
-        or die "AMF parsing requires XML::SAX\n";
+    eval qq{
+    	require Slic3r::Format::AMF::Parser;
+    	use XML::SAX::ParserFactory;
+    	1;
+    } or die "AMF parsing requires XML::SAX\n";
     
     open my $fh, '<', $file or die "Failed to open $file\n";
     
     my $model = Slic3r::Model->new;
-    XML::SAX::PurePerl
-        ->new(Handler => Slic3r::Format::AMF::Parser->new(_model => $model))
+    XML::SAX::ParserFactory
+        ->parser(Handler => Slic3r::Format::AMF::Parser->new(_model => $model))
         ->parse_file($fh);
     close $fh;
     

lib/Slic3r/Format/AMF/Parser.pm

@@ -2,8 +2,6 @@ package Slic3r::Format::AMF::Parser;
 use strict;
 use warnings;
 
-use XML::SAX::PurePerl;
-
 use base 'XML::SAX::Base';
 
 my %xyz_index = (x => 0, y => 1, z => 2); #=