diff --git a/guide/adoc/README.md b/guide/adoc/README.md
index ae7ca0d..fa7a972 100644
--- a/guide/adoc/README.md
+++ b/guide/adoc/README.md
@@ -58,9 +58,6 @@ locations in the sources.
   This would break all links to the guide. As docbookrx does not take
   configuration parameters, this has to be changed in the visitor directly.
 
-* `<link xlink:href="...">`
-  This is not converted correctly. All external links are broken.
-
 * Missing distinction between `<programlisting><prompt></><userinput></></>`, `<screen>`, and `<programlisting>`
   They all result in similar [source] blocks at the moment. Based on how they
   are used in the guide, we should keep the semantics by adding style
diff --git a/guide/xml/glossary.xml b/guide/xml/glossary.xml
index 3af1dc8..659592e 100644
--- a/guide/xml/glossary.xml
+++ b/guide/xml/glossary.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="guide-terms">
+<chapter xml:id="guide-terms" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>MacPorts Guide Glossary</title>
 
   <para>This section defines a number of words which may be new to
diff --git a/guide/xml/guide.xml b/guide/xml/guide.xml
index d4100a0..4ad2acc 100644
--- a/guide/xml/guide.xml
+++ b/guide/xml/guide.xml
@@ -4,7 +4,7 @@
 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
 
-<book>
+<book xmlns:xlink="http://www.w3.org/1999/xlink">
     <info>
         <title><application>MacPorts</application> Guide</title>
         <authorgroup>
diff --git a/guide/xml/installing.xml b/guide/xml/installing.xml
index 9011d98..80b125e 100644
--- a/guide/xml/installing.xml
+++ b/guide/xml/installing.xml
@@ -5,7 +5,7 @@
 "http://docbook.org/xml/5.0/dtd/docbook.dtd"[
 <!ENTITY macports-version "2.4.3">
 ]>
-<chapter xml:id="installing">
+<chapter xml:id="installing" xmlns:xlink="http://www.w3.org/1999/xlink">
     <title>Installing MacPorts</title>
 
     <para>This chapter shows you how to install MacPorts and its prerequisites step-by-step. Note that the section about
diff --git a/guide/xml/internals-hier.xml b/guide/xml/internals-hier.xml
index 2cca4d9..bbe4355 100644
--- a/guide/xml/internals-hier.xml
+++ b/guide/xml/internals-hier.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<refentry xml:id="porthier">
+<refentry xml:id="porthier" xmlns:xlink="http://www.w3.org/1999/xlink">
   <refmeta>
     <refentrytitle>PORTHIER</refentrytitle>
 
diff --git a/guide/xml/internals-tests.xml b/guide/xml/internals-tests.xml
index a65c218..cc47233 100644
--- a/guide/xml/internals-tests.xml
+++ b/guide/xml/internals-tests.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="internals.tests">
+<section xml:id="internals.tests" xmlns:xlink="http://www.w3.org/1999/xlink">
     <title>Tests</title>
 
     <para>
diff --git a/guide/xml/internals.xml b/guide/xml/internals.xml
index c43160c..c861188 100644
--- a/guide/xml/internals.xml
+++ b/guide/xml/internals.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="internals">
+<chapter xml:id="internals" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>MacPorts Internals</title>
 
   <para>This chapter contains information about the MacPorts file layout,
diff --git a/guide/xml/intro.xml b/guide/xml/intro.xml
index 85e945b..019c790 100644
--- a/guide/xml/intro.xml
+++ b/guide/xml/intro.xml
@@ -3,7 +3,7 @@
 -->
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="introduction">
+<chapter xml:id="introduction" xmlns:xlink="http://www.w3.org/1999/xlink">
     <title>Introduction</title>
 
     <para>MacPorts is an easy to use system for compiling, installing, and managing open source software. MacPorts may
diff --git a/guide/xml/macports.conf.xml b/guide/xml/macports.conf.xml
index 0bed976..9c28f17 100644
--- a/guide/xml/macports.conf.xml
+++ b/guide/xml/macports.conf.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="internals.configuration-files">
+<section xml:id="internals.configuration-files" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Configuration Files</title>
 
   <para>The MacPorts configuration files often do not need to be modified for the
diff --git a/guide/xml/macros.xml b/guide/xml/macros.xml
index 50669f8..7d4c4d7 100644
--- a/guide/xml/macros.xml
+++ b/guide/xml/macros.xml
@@ -3,7 +3,7 @@
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
 
 <!-- This section will be hidden by a xsl:template in resources/base.xsl -->
-<chapter xml:id='macros'>
+<chapter xml:id='macros' xmlns:xlink="http://www.w3.org/1999/xlink">
 <title>Macros</title>
 
 <!-- Marks a section as outdated with a reason. -->
diff --git a/guide/xml/portfile-dependencies.xml b/guide/xml/portfile-dependencies.xml
index 8f39a22..7ed3412 100644
--- a/guide/xml/portfile-dependencies.xml
+++ b/guide/xml/portfile-dependencies.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.dependencies">
+<section xml:id="reference.dependencies" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Dependencies</title>
 
   <para>Free and open source software is highly modular, and MacPorts ports
diff --git a/guide/xml/portfile-keywords.xml b/guide/xml/portfile-keywords.xml
index 77559a4..37477dc 100644
--- a/guide/xml/portfile-keywords.xml
+++ b/guide/xml/portfile-keywords.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.keywords">
+<section xml:id="reference.keywords" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Global Keywords</title>
 
   <para>MacPorts keywords are used to specify required or optional items
diff --git a/guide/xml/portfile-livecheck.xml b/guide/xml/portfile-livecheck.xml
index 5b2e210..4de24c0 100644
--- a/guide/xml/portfile-livecheck.xml
+++ b/guide/xml/portfile-livecheck.xml
@@ -2,7 +2,7 @@
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
 
-<section xml:id="reference.livecheck">
+<section xml:id="reference.livecheck" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Livecheck / Distcheck</title>
 
   <para>Options livecheck and distcheck are especially useful for port
diff --git a/guide/xml/portfile-phase.xml b/guide/xml/portfile-phase.xml
index f5316e5..13eda29 100644
--- a/guide/xml/portfile-phase.xml
+++ b/guide/xml/portfile-phase.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.phases">
+<section xml:id="reference.phases" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Port Phases</title>
 
   <section xml:id="reference.phases.introduction">
diff --git a/guide/xml/portfile-startupitem.xml b/guide/xml/portfile-startupitem.xml
index b349f83..59dc2a9 100644
--- a/guide/xml/portfile-startupitem.xml
+++ b/guide/xml/portfile-startupitem.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.startupitems">
+<section xml:id="reference.startupitems" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>StartupItems</title>
 
   <para>A StartupItem is a MacPorts facility to run <quote>daemons,</quote> a Unix term for
diff --git a/guide/xml/portfile-tcl.xml b/guide/xml/portfile-tcl.xml
index 237e30a..ed7a6f5 100644
--- a/guide/xml/portfile-tcl.xml
+++ b/guide/xml/portfile-tcl.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.tcl-extensions">
+<section xml:id="reference.tcl-extensions" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Tcl Extensions &amp; Useful Tcl Commands</title>
 
   <para>A MacPorts Portfile is a Tcl script, so it may contain any arbitrary
diff --git a/guide/xml/portfile-variables.xml b/guide/xml/portfile-variables.xml
index 838b808..e5af512 100644
--- a/guide/xml/portfile-variables.xml
+++ b/guide/xml/portfile-variables.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.variables">
+<section xml:id="reference.variables" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Global Variables</title>
 
   <para>Global variables are variables available to any Portfile. For a list
diff --git a/guide/xml/portfile-variants.xml b/guide/xml/portfile-variants.xml
index 0913ad8..d419642 100644
--- a/guide/xml/portfile-variants.xml
+++ b/guide/xml/portfile-variants.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.variants">
+<section xml:id="reference.variants" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Variants</title>
 
   <para>MacPorts variants are conditional modifications of port installation
diff --git a/guide/xml/portfiledev.xml b/guide/xml/portfiledev.xml
index 51ea6b6..c7f9c84 100644
--- a/guide/xml/portfiledev.xml
+++ b/guide/xml/portfiledev.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="development">
+<chapter xml:id="development" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Portfile Development</title>
 
   <para>A port is a distribution of software that can be compiled and
diff --git a/guide/xml/portfileref.xml b/guide/xml/portfileref.xml
index c68b788..368eb3e 100644
--- a/guide/xml/portfileref.xml
+++ b/guide/xml/portfileref.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="reference">
+<chapter xml:id="reference" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Portfile Reference</title>
 
   <para>This chapter serves as a reference for the major elements of a
diff --git a/guide/xml/portgroup-github.xml b/guide/xml/portgroup-github.xml
index 4566ce1..9dff2aa 100644
--- a/guide/xml/portgroup-github.xml
+++ b/guide/xml/portgroup-github.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.github">
+<section xml:id="reference.portgroup.github" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup github</title>
 
diff --git a/guide/xml/portgroup-gnustep.xml b/guide/xml/portgroup-gnustep.xml
index 2527d68..c5121f2 100644
--- a/guide/xml/portgroup-gnustep.xml
+++ b/guide/xml/portgroup-gnustep.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.gnustep">
+<section xml:id="reference.portgroup.gnustep" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup gnustep</title>
 
diff --git a/guide/xml/portgroup-haskell.xml b/guide/xml/portgroup-haskell.xml
index c69d3c2..915da5a 100644
--- a/guide/xml/portgroup-haskell.xml
+++ b/guide/xml/portgroup-haskell.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.haskell">
+<section xml:id="reference.portgroup.haskell" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup haskell</title>
 
diff --git a/guide/xml/portgroup-perl.xml b/guide/xml/portgroup-perl.xml
index 948f3db..6d17cf8 100644
--- a/guide/xml/portgroup-perl.xml
+++ b/guide/xml/portgroup-perl.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.perl">
+<section xml:id="reference.portgroup.perl" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup perl5</title>
 
diff --git a/guide/xml/portgroup-python.xml b/guide/xml/portgroup-python.xml
index 8a0408e..5153f56 100644
--- a/guide/xml/portgroup-python.xml
+++ b/guide/xml/portgroup-python.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.python">
+<section xml:id="reference.portgroup.python" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup python</title>
 
diff --git a/guide/xml/portgroup-ruby.xml b/guide/xml/portgroup-ruby.xml
index 6017e5c..afd8e84 100644
--- a/guide/xml/portgroup-ruby.xml
+++ b/guide/xml/portgroup-ruby.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.ruby">
+<section xml:id="reference.portgroup.ruby" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup ruby</title>
 
diff --git a/guide/xml/portgroup-xcode.xml b/guide/xml/portgroup-xcode.xml
index a7a47c4..a74729f 100644
--- a/guide/xml/portgroup-xcode.xml
+++ b/guide/xml/portgroup-xcode.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.xcode">
+<section xml:id="reference.portgroup.xcode" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>PortGroup xcode</title>
 
   <para><code>PortGroup xcode</code> allows for efficient porting of
diff --git a/guide/xml/portgroups.xml b/guide/xml/portgroups.xml
index 9fe8e87..9ea6671 100644
--- a/guide/xml/portgroups.xml
+++ b/guide/xml/portgroups.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<section xml:id="reference.portgroup.intro">
+<section xml:id="reference.portgroup.intro" xmlns:xlink="http://www.w3.org/1999/xlink">
 
   <title>PortGroup Introduction</title>
 
diff --git a/guide/xml/project.xml b/guide/xml/project.xml
index 56d9b92..90cfc7a 100644
--- a/guide/xml/project.xml
+++ b/guide/xml/project.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V5.0//EN"
 "http://docbook.org/xml/5.0/dtd/docbook.dtd">
-<chapter xml:id="project">
+<chapter xml:id="project" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>MacPorts Project</title>
 
   <section xml:id="project.tickets">
diff --git a/guide/xml/using.xml b/guide/xml/using.xml
index 224d214..ecdfc60 100644
--- a/guide/xml/using.xml
+++ b/guide/xml/using.xml
@@ -6,7 +6,7 @@
 <!ENTITY macports-prev-version "2.4.2">
 <!ENTITY macports-version "2.4.3">
 ]>
-<chapter xml:id="using">
+<chapter xml:id="using" xmlns:xlink="http://www.w3.org/1999/xlink">
     <title>Using MacPorts</title>
 
     <para>This chapter describes using <command>port</command>, port variants, common tasks and port