fallback-echo, finding a suitable $ECHO

[Ralf Wildenhues]

Which systems do actually need libtool's --fallback-echo?
(You can
  grep -i '^echo=.*fallback-echo' libtool 
to find out).
I would like to kill it, that would clean up initialization a bit.

Of those machines, which ones would have problems with this replacement:
(be it input size limitation, forgetting to unlink the here document
temp file, symlink-farming to child processes, creating the here doc at
definition time, whatever?)

func_fallback_echo ()
{
    # Without the eval, Bourne shells create the here doc at definition time.
    eval 'cat <<_LT_EOF
$*
_LT_EOF
'
    :   # work around bash bug
}

(Thanks to Sven Mascheck's for the hint on his site, BTW.)

On a related note: Is there a way to reliably find out whether a command
is a builtin or not?  I have attached a small script, and encourage
people to test it on all their shells they can find on their systems.
It should reveal at least one working echo, and, in most cases, find
builtins to do the job.

Thanks,
Ralf