patch from kai to fix disable-fltk-client argument

git-svn-id: svn+ssh://jackaudio.org/trunk/jack@15 0c269be4-1314-0410-8aa9-9f06e86f4224

configure.in

@@ -41,7 +41,7 @@ XTRA=""
 AC_ARG_ENABLE(fltk-client,
      [  --enable-fltk-client    build the FLTK test client.])
 
-if test "x$enable_fltk_client" != "no" ; then
+if test "x$enable_fltk_client" != "xno" ; then
      AC_CHECK_LIB(fltk,main,
          [ XTRA="$XTRA jack_fltk_client" ],
          [ AC_MSG_ERROR([*** you can't build the FLTK client without the FLTK library])],