LTDL path problems guile 1.8.5

[Roland Orre]

I finally see the only way out of my 64-bits problems to upgrade to 1.8

The problem, configure fails in the test for ltdl
I downloaded libtool-2.2.4, which seemed to be the latest
from  http://www.gnu.org/software/libtool/

I installed it under the guile directory so 
that the libltdl/lib/ is first in LD_LIBRARY_PATH and
libltdl/bin is first in PATH
but configure fails on 
checking for lt_dlinit in -lltdl... 
test ${ac_cv_lib_ltdl_lt_dlinit+set} = set

configure: error: libltdl not found.  See README.

The README was not very helpful on this issue and
I can not find where the 
ac_cv_lib_ltdl_lt_dlinit+set
would possibly be set, I don't even understand what
the syntax ${ac_cv_lib_ltdl_lt_dlinit+set} means

I also tried with a git snapshot, but when running
./autogen.sh it needs a utility named gnulib-tool which
is referenced at several places on the web, but not found
anywhere. Is this the same as above libtool so I'm
expected to make a link from libtool to gnulib-tool ?

        Best regards
        Roland