Fix doxygen warn message display

git-svn-id: svn+ssh://jackaudio.org/trunk/jack@169 0c269be4-1314-0410-8aa9-9f06e86f4224

configure.in

@@ -83,7 +83,7 @@ fi
 
 # you need doxygen to make dist.
 AC_CHECK_PROG(HAVE_DOXYGEN, doxygen, true, false)
-if test $HAVE_SNDFILE = "false"; then
+if test $HAVE_DOXYGEN = "false"; then
              AC_MSG_WARN([*** doxygen not found, docs will not be built])
 fi