libtool stdout output format

[Ralf Wildenhues]

As of now, the output format -- "whatever libtool prints on stdout" --
is different between the 1.5 releases and CVS HEAD.  The latter
prepends a string like
  libtool: $mode: 
where mode is either `compile', `link', or similar.

This output has never been formally specified, neither is it completely
uniform (which most likely is a bug in itself), also the demand to be
able to turn it off ("--quiet --quiet") has not been implemented yet.

But: there exist client packages which attempt to "parse" this
output.  libtool-cache does it, OpenMPI does it, to name but two.
When we release with this prefix string, they will have to adapt (if
they haven't already).  So, one question is: can or should we
document how this output looks like (so that at least post 2.0 this
is stable), should we provide a way to turn the prefix off, should
we just remove it entirely?  Or should we just ditch our users and
say, the heck, we didn't formally specify this (except showing it in
the docs), they should have a hard time using it?

Note that adding a command line option to turn it off would still
break compatibility with 1.5.x; OTOH, piping output through
  sed 's,^libtool: link: ,,'
or similar is not very complicated at all, and is in fact what
libtool-cache does, I believe.

Then there is also the (small) issue that libtool.texi shows the
old format; changing to the new format would be very bad w.r.t line
breaks in the info and DVI output..

Cheers,
Ralf

PS: Yes, this is certainly a low-key question, and I should be
working on the tough, release-critical ones..
at least you can't say I haven't done any of those yet..