Make latex optional.

[[Imported from SVN: r6686]]

cmake/modules/DuneDoc.cmake

+FIND_PACKAGE(LATEX)
+FIND_PROGRAM(IMAGEMAGICK_CONVERT convert
+  DOC "The convert program that comes with ImageMagick (available at http://www.imagemagick.org)."
+  )
+set(LATEX_USABLE ON)
+if(NOT ${LATEX_COMPILER})
+  message(WARING " Need latex to create documentation!")
+  set(LATEX_USABLE)
+endif(NOT ${LATEX_COMPILER})
+if(NOT ${BIBTEX_COMPILER})
+  message(WARING " Need bibtex to create documentation!")
+  set(LATEX_USABLE)
+endif(NOT ${BIBTEX_COMPILER})
+if(NOT ${MAKEINDEX_COMPILER})
+  message(WARING " Need makeindex to create documentation!")
+  set(LATEX_USABLE)
+endif(NOT ${MAKEINDEX_COMPILER})
+if(NOT ${IMAGEMAGICK_CONVERT})
+  message(WARNING " Need imagemagick to create latex documentation!")
+  set(LATEX_USABLE)
+endif(NOT ${IMAGEMAGICK_CONVERT})
+if(LATEX_USABLE)
+  include(UseLATEX)
+endif(LATEX_USABLE)
+
+
 # Module that provides a custom target make doc at the top level
 # directory and utility macros for creating install directives
 # that make sure that the files to be installed are previously

doc/buildsystem/CMakeLists.txt

-include(UseLATEX)
-ADD_LATEX_DOCUMENT(buildsystem.tex FATHER_TARGET doc DEFAULT_PDF INPUTS ../Makefile.am ../../configure.ac ../example.opts)
-create_doc_install(${CMAKE_CURRENT_BINARY_DIR}/buildsystem.pdf share/doc/dune-common/buildsystem)
+if(LATEX_USABLE)
+  ADD_LATEX_DOCUMENT(buildsystem.tex FATHER_TARGET doc DEFAULT_PDF INPUTS ../Makefile.am ../../configure.ac ../example.opts)
+  create_doc_install(${CMAKE_CURRENT_BINARY_DIR}/buildsystem.pdf share/doc/dune-common/buildsystem)
+endif(LATEX_USABLE)
 #add_custom_target(install_buildsystem)
 #install(CODE "execute_process(COMMAND \"${CMAKE_COMMAND}\" --build \"${CMAKE_BINARY_DIR}\" --target buildsystem_install )")
 #install(FILES ${CMAKE_CURRENT_BINARY_DIR}/buildsystem.pdf