autoconf: --with-online= is optional now

configure.ac

@@ -113,7 +113,7 @@ AM_CONDITIONAL(USE_DARSHAN, [test "x${use_darshan}" = xyes])
 AC_ARG_WITH([online],[AS_HELP_STRING([--with-online@<:@=DIR@:>@],
                         [Build with the online workloads and argobots support])],
                       [use_online=yes],[use_online=no])
-if test "x${use_online}" != "x" ; then
+if test "x${use_online}" != "xno" ; then
     AM_CONDITIONAL(USE_ONLINE, true)
     PKG_CHECK_MODULES_STATIC([ARGOBOTS], [argobots], [],
                       [AC_MSG_ERROR([Could not find working argobots installation via pkg-config])])