quadratic behavior for variable append

[Ralf Wildenhues]

GNU Libtool suffers[1] from the fact that repeated concatenation

  var=
  for elem in $long_list
  do
    var="$var $elem"
  done

scales quadratically in the number of list elements.  Now while most if
not all common shells exhibit this behavior, and it happens even when
you append a constant string, I do think it is a bug, and should be
fixed.  Last tested with
| GNU bash, version 3.00.14(1)-release (x86_64-redhat-linux-gnu)

Please keep me in Cc:, I'm not subscribed.

Regards,
Ralf

[1] http://lists.gnu.org/archive/html/libtool-patches/2005-05/msg00050.html
and proposed workaround with temp files (3rd attachment):
http://lists.gnu.org/archive/html/libtool-patches/2005-05/msg00076.html