Don't unzip the sources which were bundled originally. Guix strips them from
the source and uses pre-build packages.

Taken from https://anonscm.debian.org/viewvc/pkg-java/trunk/libxerces2-java/debian/patches/02_build_dont_unzip.patch?revision=14507

Index: b/build.xml
===================================================================
--- a/build.xml
+++ b/build.xml
@@ -247,7 +247,7 @@
     <copy file="${src.dir}/org/apache/xerces/impl/xpath/regex/message.properties"
       tofile="${build.src}/org/apache/xerces/impl/xpath/regex/message_en.properties"/>
 
-    <!-- now deal with API's:  -->
+    <!-- not needed for Debian
     <unzip src="${src.apis.zip}" dest="${build.src}">
         <patternset
             includes="org/xml/sax/** 
@@ -270,6 +270,7 @@
                 org/w3c/dom/xpath/**"
         />
     </unzip>
+    -->
     
     <!-- substitute tokens as needed -->
     <replace file="${build.dir}/src/org/apache/xerces/impl/Version.java" 
@@ -1232,7 +1233,7 @@
     <replace file="${build.dir}/src/org/apache/xerces/parsers/AbstractSAXParser.java"
              token="return (fConfiguration instanceof XML11Configurable);" value="return false;"/>
  
-    <!-- now deal with API's:  -->
+    <!-- not needed for Debian
     <unzip src="${src.apis.zip}" dest="${build.src}">
         <patternset
             includes="org/xml/sax/** 
@@ -1255,7 +1256,7 @@
                 org/w3c/dom/xpath/**"
         />
     </unzip>
-
+    -->
 
     <!-- substitute tokens as needed -->
     <replace file="${build.dir}/src/org/apache/xerces/impl/Version.java" 
/gnu/packages/cross-base.scm'>
<input type='hidden' name='id' value='f8953bea858f894b406eed4a0aca0cd4c4d8671d'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>root</a>/<a href='/guix/log/gnu?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>gnu</a>/<a href='/guix/log/gnu/packages?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>packages</a>/<a href='/guix/log/gnu/packages/cross-base.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>cross-base.scm</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/gnu/packages/cross-base.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d&amp;s<tr><td><span title='2020-11-07 15:35:07 +0100'>2020-11-07</span></td><td><a href='/guix/commit/gnu/packages/zile.scm?id=afe02a6df4dac7ab81084fef88796b3fdc88de7c'>gnu: zile: Update to 2.4.15.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/zile.scm (zile): Update to 2.4.15.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
 gnu/packages/cross-base.scm (cross-gcc-arguments): Add
"--with-long-double-128" when TARGET is "powerpc64le-linux-gnu".
* gnu/packages/commencement.scm (gcc-boot0): Likewise for (boot-triplet).

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>dftxbs3e</td></tr>
<tr><td><span title='2020-11-08 16:58:30 +0100'>2020-11-08</span></td><td><a href='/guix/commit/gnu/packages/cross-base.scm?id=bc47583412745e38d994a4ba71cda6564aed3a35'>gnu: cross-base: Move glibc Hurd patches to 'inputs'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes "guix build --target=i586-pc-gnu bootstrap-tarballs".

* gnu/packages/cross-base.scm (cross-libc): Move Hurd patches from
'native-inputs' to 'inputs'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-26 23:29:19 +0200'>2020-06-26</span></td><td><a href='/guix/commit/gnu/packages/cross-base.scm?id=00410bbeafc5e0247f8fb9a63b7919f8cbe6a655'>gnu: mig: Do not assume "perl" to be available.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/hurd.scm (mig)[inputs]: Include perl.
[arguments]: Substitute "perl" with full store file name in bin/mig.
* gnu/packages/cross-base.scm (cross-kernel-headers): Adjust mig-cross
accordingly.
</span></span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>