Ensure that m4 --version actually outputs 1.4 and not 1.4o.
Some rpms are mislabeled in that area.
Otherwise, the only problem source comes from having a
"polluted" installation where multiple autoconf/libtool
versions are sprinkled through the whole system.
Thanks for the help :-)
The problem was that the libtool sources contained a file libtool.m4 of zero
bytes in size. After adding a correct file to the sorce directory and building
everything again it works now: Thanks to Jani & Sascha
regards
marcus