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">
b600'/><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=ee1bed9d64fe923c2733d368e353dc9a6789b600'>root</a>/<a href='/guix/log/tests?id=ee1bed9d64fe923c2733d368e353dc9a6789b600'>tests</a>/<a href='/guix/log/tests/services.scm?id=ee1bed9d64fe923c2733d368e353dc9a6789b600'>services.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/tests/services.scm?id=ee1bed9d64fe923c2733d368e353dc9a6789b600&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-07-26 19:19:49 +0200'>2019-07-26</span></td><td><a href='/guix/commit/tests/services.scm?id=5c793753b31b1dcd9a554bce953124f7ae88ca9a'>guix system: Add 'reconfigure' module.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/system/reconfigure.scm: New file.
* Makefile.am (MODULES): Add it.
* guix/scripts/system.scm (bootloader-installer-script): Export variable.
* gnu/machine/ssh.scm (switch-to-system, upgrade-shepherd-services)
(install-bootloader): Delete variable.
* gnu/machine/ssh.scm (deploy-managed-host): Rewrite procedure.
* gnu/services/herd.scm (live-service): Export variable.
* gnu/services/herd.scm (live-service-canonical-name): New variable.
* tests/services.scm (live-service): Delete variable.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Jakob L. Kreuze</td></tr>
<tr><td><span title='2019-01-24 20:47:21 +0100'>2019-01-24</span></td><td><a href='/guix/commit/tests/services.scm?id=2c5ee9bba4067fb0a9e68fb2af3a6e7fe36960cb'>tests: Remove duplicate field initializers.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes a regression introduced in
c2dcff41c2e47f5f978f467864d5ed7829939884, whereby many tests in
'tests/packages.scm' would trigger a syntax error due to duplicate field
intializers in forms like:

  (dummy-package "foo" (version "0"))

* guix/tests.scm (dummy-package, dummy-origin): Rewrite to inherit from
a base record.  This restores the semantics from before
c2dcff41c2e47f5f978f467864d5ed7829939884.
* tests/services.scm ("instantiate-missing-services, indirect"): Remove
duplicate 'extensions' field.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-27 23:58:05 +0200'>2018-09-27</span></td><td><a href='/guix/commit/tests/services.scm?id=7fed9353ece5974ff431fa666a530da237a12085'>tests: Adjust services tests to new 'shepherd-service-upgrade'.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 4245ddcbc9f935804c17c97872b90ec1050c2d75.

* tests/services.scm ("shepherd-service-upgrade: one unchanged, one upgraded, one new")
("shepherd-service-upgrade: service depended on is not unloaded")
("shepherd-service-upgrade: obsolete services that depend on each
other"): Adjust to changes in 'shepherd-service-upgrade'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-07 23:00:39 +0200'>2018-09-07</span></td><td><a href='/guix/commit/tests/services.scm?id=9b6c4355645534d1ae799bfef6761b75ed8b3a41'>services: 'instantiate-missing-services' reaches fixed point.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes a bug whereby services indirectly depended on would not be
automatically instantiated.

* gnu/services.scm (instantiate-missing-services): Loop back when the
length of ADJUSTED is greater than that of INSTANCES.
* tests/services.scm ("instantiate-missing-services, indirect"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-01-21 00:24:03 +0100'>2018-01-21</span></td><td><a href='/guix/commit/tests/services.scm?id=d466b1fc8221a6224fe7ded53a828f9c29ed9457'>services: Missing services are automatically instantiated.</a><span class='msg-avail'>...<span class='msg-tooltip'>This simplifies OS configuration: users no longer need to be aware of
what a given service depends on.

See the discussion at
&lt;https://lists.gnu.org/archive/html/guix-devel/2018-01/msg00114.html&gt;.

* gnu/services.scm (missing-target-error): New procedure.
(service-back-edges): Use it.
(instantiate-missing-services): New procedure.
* gnu/system.scm (operating-system-services): Call
'instantiate-missing-services'.
* tests/services.scm ("instantiate-missing-services")
("instantiate-missing-services, no default value"): New tests.
* gnu/services/version-control.scm (cgit-service-type)[extensions]: Add
FCGIWRAP-SERVICE-TYPE.
* gnu/tests/version-control.scm (%cgit-os): Remove NGINX-SERVICE-TYPE
and FCGIWRAP-SERVICE-TYPE instances.
* doc/guix.texi (Log Rotation): Remove 'mcron-service-type' in example.
(Miscellaneous Services): Remove 'nginx-service-type' and
'fcgiwrap-service-type' in Cgit example.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-11-08 22:31:58 +0100'>2017-11-08</span></td><td><a href='/guix/commit/tests/services.scm?id=49483f71381ad32cdbe81b1c8ed2cc023329cc18'>services: Add 'lookup-service-types'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services.scm (lookup-service-types): New procedure.
* tests/services.scm ("lookup-service-types"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>