Based on https://anonscm.debian.org/viewvc/pkg-java/trunk/libxerces2-java/debian/patches/03_bootclasspath.patch?revision=14509, adopted for guix

--- xerces-2_11_0/build.xml.orig	2010-11-26 21:42:11.000000000 +0100
+++ xerces-2_11_0/build.xml	2017-03-28 14:04:41.946606996 +0200
@@ -290,13 +290,14 @@
            destdir="${build.dest}"
            source="${javac.source}"
            target="${javac.target}"
-           classpath="${build.dir}/classes:${tools.dir}/${jar.apis}:${tools.dir}/${jar.resolver}:${tools.dir}/${jar.serializer}"
+           classpath="${build.dir}/classes:${jar.jaxp}:${jar.apis-ext}:${jar.resolver}"
            debug="${debug}" nowarn="true"
            debuglevel="${debuglevel}"
            deprecation="${deprecation}"
            optimize="${optimize}"
            includeAntRuntime="false"
-           includeJavaRuntime="false"
+           includeJavaRuntime="true"
+           bootclasspath="${jar.jaxp}:${jar.apis-ext}:${jar.resolver}"
            excludes="org/xml/sax/** 
                 javax/xml/**
                 org/w3c/dom/*
@@ -1451,13 +1452,14 @@
                destdir="${build.dest}"
                source="${javac.source}"
                target="${javac.target}"
-               classpath="${build.dir}/classes:${tools.dir}/${jar.apis}:${tools.dir}/${jar.resolver}:${tools.dir}/${jar.serializer}"
+               classpath="${build.dir}/classes:${jar.jaxp}:${jar.apis-ext}:${jar.resolver}"
                debug="${debug}"
                debuglevel="${debuglevel}"
                deprecation="${deprecation}"
                optimize="${optimize}"
                includeAntRuntime="false"
-               includeJavaRuntime="false"
+               includeJavaRuntime="true"
+               bootclasspath="${jar.jaxp}:${jar.apis-ext}:${jar.resolver}"
                excludes="org/xml/sax/** 
                     javax/xml/**
                     org/w3c/dom/*
a href='/guix/log/?id=b46a0ee7532639817fe846233a75c758a9e7b963'>root</a>/<a href='/guix/log/po?id=b46a0ee7532639817fe846233a75c758a9e7b963'>po</a>/<a href='/guix/log/po/packages?id=b46a0ee7532639817fe846233a75c758a9e7b963'>packages</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/po/packages?id=b46a0ee7532639817fe846233a75c758a9e7b963&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-05-13 22:44:22 +0200'>2019-05-13</span></td><td><a href='/guix/commit/po/packages?id=d1b18fbb5c119f16d57d08ac4264e10a0a536884'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-05-03 17:47:30 +0200'>2019-05-03</span></td><td><a href='/guix/commit/po/packages?id=adb5506b2cfb47f696d66a03ede897e9bfa829bb'>nls: Update da translations.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-01 10:49:52 +0200'>2019-05-01</span></td><td><a href='/guix/commit/po/packages?id=20ee8883bcb1d75e8e783de5254e11e7142c1e61'>nls: Update translations for de and fr.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-04-25 18:55:12 +0200'>2019-04-25</span></td><td><a href='/guix/commit/po/packages?id=57e2b24dc03e44e4e379436e63d29231f1f9d28c'>nls: Update 'es' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-04-25 18:54:46 +0200'>2019-04-25</span></td><td><a href='/guix/commit/po/packages?id=518acc73c11d0fc4118bd4f4f9220fe745d59054'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-04-13 14:50:46 +0200'>2019-04-13</span></td><td><a href='/guix/commit/po/packages?id=a27ed8fd35ce66520bc3d81dbe752841583d1482'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-02-13 21:40:17 +0100'>2019-02-13</span></td><td><a href='/guix/commit/po/packages?id=57e508d1c13cc95a37cf44ed429d1d0b97ef763d'>nls: Update 'de' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-02-13 21:40:02 +0100'>2019-02-13</span></td><td><a href='/guix/commit/po/packages?id=d093f3e4a4dd155969499ac2dc5fdb069a611c75'>nls: Update 'da' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-12-02 14:31:20 +0100'>2018-12-02</span></td><td><a href='/guix/commit/po/packages?id=adfb167f12c91731788f0b20066471274df23400'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-23 16:23:50 +0200'>2018-06-23</span></td><td><a href='/guix/commit/po/packages?id=2cf2c778846153f3d5a56e98232fbef6f71b57a6'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-18 23:19:51 +0200'>2018-06-18</span></td><td><a href='/guix/commit/po/packages?id=f202292217c0a5588d1c281014e9453ff0343c19'>nls: Update 'da' translation.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-04-19 00:14:49 +0200'>2018-04-19</span></td><td><a href='/guix/commit/po/packages?id=c88abbf2fda8f3798a0e3dd14a02157d247875e8'>nls: Update 'es' translation.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-04-11 01:21:32 +0200'>2018-04-11</span></td><td><a href='/guix/commit/po/packages?id=ac6d2e35300012ddac2eea13b09e7a20cfb02520'>nls: Add Spanish translation.</a></td><td>Ludovic Courtès</td></tr>