Re: echo vs. printf regression (darwin8)

[David Fang]

> On 08/16/2010 04:27 PM, Peter O'Gorman wrote:
> > On 08/16/2010 07:37 AM, Paolo Bonzini wrote:
> > > On 08/16/2010 12:54 AM, David Fang wrote:
> > > > Actually, 'pogma' pointed out that this comes from the autoconf macros
> > > > in libtool.m4, near AC_MSG_CHECKING([how to print strings]).
> > > > I'm using libtool-2.2.10 right now.
> > >
> > > I don't understand, is it breaking in Makefiles that you wrote? I don't
> > > know of anything in {autoconf,automake,libtool} that would use $ECHO
> > > this way.
> >
> > I think it is a namespace problem. What business does libtool have
> > setting vars like ECHO, MV, etc.
>
> That's correct.  However...
>
> > If libtool had not unconditionally set ECHO to something other than
> > 'echo', David's Makefiles would have continued to work when he moved
> > from libtool-1.5.x to libtool-2.x.
>
> ... this doesn't seem to be the case.  It looks like David's makefiles were 
> relying on the definition of ECHO that libtool provided, and this is clearly 
> an issue of using an undocumented interface.  He, or some package he used, 
> had to explicitly do AC_SUBST([ECHO]), and this is a very strong point 
> against this usage, even if the variable name doesn't show that.

I think we agree that autoconf is not at fault here. For years, I've been 
using $(ECHO) in Makefile.am's with an AC_CHECK_PROG([ECHO], echo, echo), 
up through autoconf-2.63, and libtool-2.2.6, but the latest libtool-2.2.10 
overrides ECHO in libtool.m4.  I don't recall seeing anything wrong with 
AC_CHECK_PROG(ECHO...), which does the AC_SUBST.  It just happens to be 
done before LT_INIT.  If I reorder the macros, can I expect to get back 
the old behavior, where ECHO is echo from AC_CHECK_PROG?
I leave it up to libtool devs to decide whether/how to fix.

Fang

David Fang
http://www.csl.cornell.edu/~fang/
http://www.achronix.com/