Add support for language='c++'.

The implementation is a bit odd, but I was trying to match the existing
templates.

[SVN r86509]

test/more/tests/syntax-highlight/language-attribute.gold

@@ -0,0 +1,13 @@
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<book xmlns:xi="http://www.w3.org/2001/XInclude" id="test" lang="en">
+  <title>Test language attribute</title>
+  <programlisting>plain text</programlisting>
+  <programlisting><phrase role="keyword">void</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase><phrase role="special">)</phrase> <phrase role="special">{</phrase><phrase role="special">}</phrase></programlisting>
+  <programlisting><phrase role="keyword">actions</phrase> something <phrase role="special">;</phrase></programlisting>
+
+  <para>
+    <computeroutput>plain text</computeroutput>
+    <computeroutput><phrase role="keyword">void</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase><phrase role="special">)</phrase> <phrase role="special">{</phrase><phrase role="special">}</phrase></computeroutput>
+    <computeroutput><phrase role="keyword">actions</phrase> something <phrase role="special">;</phrase></computeroutput>
+  </para>
+</book>

test/more/tests/syntax-highlight/language-attribute.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright 2013 Daniel James.
+
+    Distributed under the Boost Software License, Version 1.0.
+    (See accompanying file LICENSE_1_0.txt or copy at
+    http://www.boost.org/LICENSE_1_0.txt)
+-->
+<!DOCTYPE boostbook PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
+  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
+<boostbook id="test" xmlns:xi="http://www.w3.org/2001/XInclude"
+           last-revision="$Date: 2010-10-30 15:29:27 +0100 (Sat, 30 Oct 2010) $"
+           lang="en">
+  <title>Test language attribute</title>
+  <programlisting>plain text</programlisting>
+  <programlisting language="c++">void main() {}</programlisting>
+  <programlisting language="jam">actions something ;</programlisting>
+
+  <para>
+    <code>plain text</code>
+    <code language="c++">void main() {}</code>
+    <code language="jam">actions something ;</code>
+  </para>
+</boostbook>
+

xsl/annotation.xsl

@@ -400,6 +400,14 @@
     </computeroutput>
   </xsl:template>
 
+  <xsl:template match="code[@language='c++']" mode="annotation">
+    <computeroutput>
+      <xsl:apply-templates mode="annotation">
+        <xsl:with-param name="highlight" select="true()"/>
+      </xsl:apply-templates>
+    </computeroutput>
+  </xsl:template>
+
   <xsl:template match="bold" mode="annotation">
     <emphasis role="bold">
       <xsl:apply-templates mode="annotation"/>

xsl/docbook.xsl

@@ -398,6 +398,10 @@ Error: XSL template 'link-or-anchor' called with invalid link-type '<xsl:value-o
     </computeroutput>
   </xsl:template>
 
+  <xsl:template match="code[@language='c++']">
+    <xsl:apply-templates select="." mode="annotation"/>
+  </xsl:template>
+
   <xsl:template match="bold">
     <emphasis role="bold">
       <xsl:apply-templates mode="annotation"/>
@@ -454,6 +458,10 @@ Error: XSL template 'link-or-anchor' called with invalid link-type '<xsl:value-o
     </programlisting>
   </xsl:template>
 
+  <xsl:template match="programlisting[@language='c++']">
+    <xsl:apply-templates select="." mode="annotation"/>
+  </xsl:template>
+
   <!-- These DocBook elements have special meaning. Use the annotation mode -->
   <xsl:template match="classname|methodname|functionname|enumname|
                        macroname|headername|globalname">