Use a non-recursive replace function when the parser supports it.

https://bugs.gnu.org/29782
https://bugzilla.samba.org/show_bug.cgi?id=9515
https://bugzilla.gnome.org/show_bug.cgi?id=736077 (for xsltproc)

Patch copied from Debian:
https://salsa.debian.org/debian/docbook-xsl/-/blob/master/debian/patches/765567_non-recursive_string_subst.patch

Description: use EXSLT "replace" function when available
 A recursive implementation  of string.subst is problematic,
 long strings with many matches will cause stack overflows.
Author: Peter De Wachter <pdewacht@gmail.com>
Bug-Debian: https://bugs.debian.org/750593

--- a/lib/lib.xsl
+++ b/lib/lib.xsl
@@ -6,7 +6,11 @@
 
      This module implements DTD-independent functions
 
-     ******************************************************************** --><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
+     ******************************************************************** -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+                xmlns:str="http://exslt.org/strings"
+                exclude-result-prefixes="str"
+                version="1.0">
 
 <xsl:template name="dot.count">
   <!-- Returns the number of "." characters in a string -->
@@ -52,6 +56,9 @@
   <xsl:param name="replacement"/>
 
   <xsl:choose>
+    <xsl:when test="function-available('str:replace')">
+      <xsl:value-of select="str:replace($string, string($target), string($replacement))"/>
+    </xsl:when>
     <xsl:when test="contains($string, $target)">
       <xsl:variable name="rest">
         <xsl:call-template name="string.subst">
1ffcf4f522c7400f3b10dad17f157378'/><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=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>root</a>/<a href='/guix/log/tests?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>tests</a>/<a href='/guix/log/tests/guix-download.sh?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>guix-download.sh</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/tests/guix-download.sh?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-09-28 21:06:36 -0500'>2020-09-28</span></td><td><a href='/guix/commit/tests/guix-download.sh?id=d8934360d2453a403b5433e71d09188e4ed23b57'>tests: Simplify shell exit status negation;</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-lint.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh: Use the shell '!' keyword to negate command exit status
in place of 'if ...; then false; else true; fi'
</span></span></td><td>Eric Bavier</td></tr>