Alien::Build has been designed to build dependencies on the fly
when installing from CPAN.  That does not make sense for our ports
tree.  Remove Alien::Libxml2 references, instead link against the
library from our libxml-2 package.

Index: Makefile.PL
--- Makefile.PL.orig
+++ Makefile.PL
@@ -17,15 +17,12 @@ use warnings;
 
 require 5.008001;
 
-use Alien::Base::Wrapper qw( Alien::Libxml2 );
 use ExtUtils::MakeMaker;
 use Config;
 
 my $SKIP_SAX_INSTALL = $ENV{SKIP_SAX_INSTALL};
 
 my %ConfigReqs = (
-  "Alien::Libxml2" => '0.14',
-  "Alien::Base::Wrapper" => 0,
   "Config" => 0,
   "ExtUtils::MakeMaker" => 0,
 );
@@ -68,15 +65,13 @@ my %prereqs = (
   "warnings" => 0,
 );
 
-my %xsbuild_concat = (
+my %xsbuild = (
   DEFINE  => '-DHAVE_UTF8',
   OBJECT  => '$(O_FILES)',
+  CCFLAGS => $Config{ccflags} .
+	' -I${LOCALBASE}/include -I${LOCALBASE}/include/libxml2',
+  LIBS    => '-L${LOCALBASE}/lib -lxml2',
 );
-my %xsbuild = Alien::Base::Wrapper->mm_args;  # Might contain a definition of DEFINE, must thus concatenate.
-while (my ($k, $v) = each %xsbuild_concat) {
-  my $base_val = $xsbuild{$k};
-  $xsbuild{$k} = (defined($base_val) ? ($base_val . ' ' . $v) : $v);
-}
 
 my %WriteMakefileArgs = (
   "NAME" => "XML::LibXML",