libtool errors "command not found" and "ignoring unknown tag"

[Frank Lahm]

Hi!

I'm one of the netatalk developers. I've received a bug report through
a distro channel [1] that make is throwing errors when beginning to
compile our libtool based library. We've just recently released an
update to netatalk, the error reported is happening with the last rc
of that update which was included downstream in Debain unstable. As I
haven't changed anything in the toolchain between rc and final I'd
like to know what's going on here.
So far this issue has been only reported once. The error is (see also at [1]):
---8<---
make[4]: Entering directory `/usr/src/netatalk-2.0.4~rc2/libatalk/adouble'
/bin/sh ../../libtool --tag=CC   --mode=compile cc -DHAVE_CONFIG_H -I. -I../..
-I../../include -D_U_="__attribute__((unused))" -g -O2 -g -Wall -O2 -I../../sys
-c -o ad_open.lo ad_open.c
../../libtool: line 793: X--tag=CC: command not found
../../libtool: line 826: libtool: ignoring unknown tag : command not found
../../libtool: line 793: X--mode=compile: command not found
---8<---

Googling for the error messages pointed in the direction of
libtool/ltmain.sh version problems [2], but I don't really understand
the solution proposed in [2] and therefor this doesn't really give me
a clue on how to fix is. A tarball with the exact package throwing the
error could be downloaded at [3].

I can not reproduce this error nor canst the Debain package
maintainer. The version of the distributed ltmain.sh is
VERSION="1.5.22 Debian 1.5.22-4".

Our configure.in calls AC_LIBTOOL_DLOPEN and then AC_PROG_LIBTOOL,
we're bootstrapping by:
libtoolize --copy --force && \
        aclocal -I macros $ACLOCAL_FLAGS && \
        autoheader && \
        automake --include-deps --add-missing --foreign && \
        autoconf

I'm not really that familiar with the inner workings of libtool and
thus am at my wits end. Any pointers are highly appreciated!

Thanks!
-Frank

[1] <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=533141>
[2] <http://www.mail-archive.com/address@hidden/msg10816.html>
[3] 
<http://ftp.de.debian.org/debian/pool/main/n/netatalk/netatalk_2.0.4~rc2.orig.tar.gz>