docbook-xsl-ns: Add patch to avoid infinite recursion.

Fixes #39090

pkgs/data/sgml+xml/stylesheets/xslt/docbook-xsl/default.nix

@@ -60,6 +60,7 @@ in {
   docbook_xsl_ns = common {
     pname = "docbook-xsl-ns";
     sha256 = "170ggf5dgjar65kkn5n33kvjr3pdinpj66nnxfx8b2avw0k91jin";
-  };
 
+    patches = [ ./docbook-xsl-ns-infinite.patch ];
+  };
 }

pkgs/data/sgml+xml/stylesheets/xslt/docbook-xsl/docbook-xsl-ns-infinite.patch

@@ -0,0 +1,31 @@
+Description: Remove infinite recursion
+Attribute: docbook5_xsl
+Version: 1.79.1
+URL: https://github.com/NixOS/nixpkgs/issues/39090
+diff -ru a/lib/lib.xsl b/lib/lib.xsl
+--- a/lib/lib.xsl	2015-12-26 15:15:37.000000000 -0800
++++ b/lib/lib.xsl	2018-03-22 11:52:45.311949264 -0700
+@@ -11,8 +11,11 @@
+ 
+      ******************************************************************** -->
+ <xsl:stylesheet exclude-result-prefixes="d"
+-                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:d="http://docbook.org/ns/docbook"
+-version="1.0">
++                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
++                xmlns:d="http://docbook.org/ns/docbook"
++                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 -->
+@@ -58,6 +61,9 @@
+   <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">