doc/doxygen: need a version of doxygen greater or equal to 1.8

configure.ac

@@ -2179,11 +2179,21 @@ AC_ARG_ENABLE(build-doc, [AS_HELP_STRING([--disable-build-doc],
 AC_PATH_PROG(doxygencommand, doxygen)
 if test "$doxygencommand" = "" ; then
 	enable_build_doc="no"
+else
+	DOXYGEN_VERSION_MAJOR=`$doxygencommand --version| cut -d '.' -f1`
+	DOXYGEN_VERSION_MINOR=`$doxygencommand --version| cut -d '.' -f2`
+	if test $DOXYGEN_VERSION_MAJOR -ge 1 -a $DOXYGEN_VERSION_MINOR -ge 8 ; then
+	   	enable_build_doc="yes"
+	else
+	   	enable_build_doc="no"
+	fi
 fi
 AC_PATH_PROG(pdflatex, pdflatex)
 if test "pdflatexcommand" = "" ; then
 	enable_build_doc="no"
 fi
+AC_MSG_CHECKING(whether documentation should be compiled)
+AC_MSG_RESULT($enable_build_doc)
 
 AM_CONDITIONAL(BUILD_DOC, [test x$enable_build_doc != xno])