default configure arguments

[Mirar]

I would like to store default configure arguments in a separate file
in the source tree (so I can erase the build tree without losing the
configure arguments).

How is this done best?

  AC_INIT...
  AC_CONFIG_HEADER...

  if test -e "$srcdir/configure_args"; then
      ac_arg="`cat "$srcdir/configure_args" | sed "s/'/'\\\\\\\\''/g"`"
      ac_configure_args="$ac_arg $ac_configure_args"
      echo "$ac_configure_args"
  fi

might work, but is probably very very bad.

Any suggestions?

/Mirar