Fix recursion accounting in XPath expressions:

  https://gitlab.gnome.org/GNOME/libxml2/-/issues/264

Taken from upstream:

  https://gitlab.gnome.org/GNOME/libxml2/-/commit/3e1aad4fe584747fd7d17cc7b2863a78e2d21a77

diff --git a/xpath.c b/xpath.c
--- a/xpath.c
+++ b/xpath.c
@@ -10983,7 +10983,7 @@ xmlXPathCompileExpr(xmlXPathParserContextPtr ctxt, int sort) {
     }
 
     if (xpctxt != NULL)
-        xpctxt->depth -= 1;
+        xpctxt->depth -= 10;
 }
 
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<tr><td><span title='2022-07-12 01:17:45 +0200'>2022-07-12</span></td><td><a href='/guix/commit/guix.scm?id=4574ef267e543bcac97d9c400f30cb731df29181'>guix: Really export 'define-public'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-09-14 11:50:58 +0200'>2021-09-14</span></td><td><a href='/guix/commit/guix.scm?id=3858275962f1ac567b5dce2355035f9eddea0a05'>guix: Replace 'define-public'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-06-29 00:00:13 +0200'>2021-06-29</span></td><td><a href='/guix/commit/guix.scm?id=e059adcb6001ab0353d969b24030d0c342f8830e'>(guix) no longer pulls in (guix ftp-client).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>