In configure.in:

AC_MSG_CHECKING(whether to enable a memory limit)
AC_ARG_ENABLE(memory-limit,
[  --enable-memory-limit   Compile with memory limit support. ],
[
  if test "$enableval" = "yes"; then
    AC_DEFINE(MEMORY_LIMIT, 1)
    AC_MSG_RESULT(yes)
  else
    AC_DEFINE(MEMORY_LIMIT, 0)
    AC_MSG_RESULT(no)
  fi
],[
  AC_DEFINE(MEMORY_LIMIT, 1)
  AC_MSG_RESULT(no)
])

In the default action (the last AC_DEFINE) it's being set to
1, but AC_MSG_RESULT is saying "no" it should either say yes,
or be set to 0. Since the text is enable-memory-limit it
seems the intent was for it to be disabled by default?