CMake: Discover docbook stylesheet in other locations

Distributions seem to install this stuff all over the place, so
let's add a common list of paths we know about.

CMake/Documentation.cmake

@@ -24,6 +24,34 @@
 # SOFTWARE.
 
 
+find_path(DOCBOOK_XSL manpages/docbook.xsl
+         # Debian
+         /usr/share/xml/docbook/stylesheet/docbook-xsl
+         /usr/share/xml/docbook/stylesheet/nwalsh
+         # OpenSUSE
+         /usr/share/xml/docbook/stylesheet/nwalsh/current
+         # Arch
+          /usr/share/xml/docbook/xsl-stylesheets
+         # Fedora
+         /usr/share/sgml/docbook/xsl-stylesheets
+         # Fink
+         ${CMAKE_INSTALL_PREFIX}/share/xml/xsl/docbook-xsl
+         # FreeBSD
+         ${CMAKE_INSTALL_PREFIX}/share/xsl/docbook/
+         NO_DEFAULT_PATH)
+
+if(NOT DOCBOOK_XSL)
+    message(FATAL_ERROR "Could not find docbook xsl")
+endif()
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/docbook-text-style.xsl.cmake.in
+                ${CMAKE_CURRENT_BINARY_DIR}/docbook-text-style.xsl)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/docbook-html-style.xsl.cmake.in
+                ${CMAKE_CURRENT_BINARY_DIR}/docbook-html-style.xsl)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/manpage-style.xsl.cmake.in
+                ${CMAKE_CURRENT_BINARY_DIR}/manpage-style.xsl)
+
+
 # Split up a string of the form DOCUMENT[.DOCUMENT][.LANGUAGE][.SECTION].EXTENSION
 #
 # There might be up to two parts in the document name. The language must be
@@ -123,7 +151,7 @@ function(xsltproc_one)
         else()
         set(manpage_output "${CMAKE_CURRENT_BINARY_DIR}/${document}.${section}")
         endif()
-        set(manpage_stylesheet "${CMAKE_CURRENT_SOURCE_DIR}/manpage-style.xsl")
+        set(manpage_stylesheet "${CMAKE_CURRENT_BINARY_DIR}/manpage-style.xsl")
         set(manpage_params)
 
         install(FILES ${manpage_output}
@@ -137,7 +165,7 @@ function(xsltproc_one)
         set(html_output "${CMAKE_CURRENT_BINARY_DIR}/${document}.html")
         endif()
         set(html_params --stringparam base.dir ${html_output})
-        set(html_stylesheet "${CMAKE_CURRENT_SOURCE_DIR}/docbook-html-style.xsl")
+        set(html_stylesheet "${CMAKE_CURRENT_BINARY_DIR}/docbook-html-style.xsl")
         install(DIRECTORY ${html_output}
                 DESTINATION ${DOC_INSTALL}
                 OPTIONAL)
@@ -150,7 +178,7 @@ function(xsltproc_one)
         set(text_output "${CMAKE_CURRENT_BINARY_DIR}/${document}.text")
         endif()
         set(text_params --stringparam base.dir ${text_output})
-        set(text_stylesheet "${CMAKE_CURRENT_SOURCE_DIR}/docbook-text-style.xsl")
+        set(text_stylesheet "${CMAKE_CURRENT_BINARY_DIR}/docbook-text-style.xsl")
 
         file(RELATIVE_PATH text_output_relative ${CMAKE_CURRENT_BINARY_DIR} ${text_output})
 

doc/docbook-html-style.xsl

@@ -2,7 +2,7 @@
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
 
   <!-- Import our base stylesheet -->
-  <xsl:import href="/usr/share/xml/docbook/stylesheet/docbook-xsl/xhtml-1_1/chunk.xsl" />
+  <xsl:import href="@DOCBOOK_XSL@/xhtml-1_1/chunk.xsl" />
 
   <!-- Since we use xsltproc (not saxon), add a workaround to ensure UTF-8 -->
   <xsl:template xmlns="http://www.w3.org/1999/xhtml" name="head.content.generator">

doc/docbook-text-style.xsl

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
 
-  <xsl:import href="/usr/share/xml/docbook/stylesheet/docbook-xsl/xhtml-1_1/docbook.xsl" />
+  <xsl:import href="@DOCBOOK_XSL@/xhtml-1_1/docbook.xsl" />
 
   <!-- Parameters for optimal text output. -->
   <xsl:param name="callout.graphics" select="0"/>

doc/manpage-style.xsl

@@ -2,7 +2,7 @@
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  version="1.0">
 
-<xsl:import href="/usr/share/xml/docbook/stylesheet/nwalsh/manpages/docbook.xsl" />
+<xsl:import href="@DOCBOOK_XSL@/manpages/docbook.xsl" />
 
 <xsl:param name="man.output.encoding" select="'UTF-8'" />