Problem compiling gnunet

I downloaded GNUnet-0.6.1.tar.bz2. After installing libextractor-0.2.6 
from the sources (without problem) and decompressing 
GNUnet-0.6.1.tar.bz2, I ran the command :

$ ./configure --prefix=$HOME

There was apparently no problem. Then I did :

$ make

And I got the following error message :

 gcc -DHAVE_CONFIG_H -I. -I. -I../../src/include 
-DPLUGIN_PATH=\"/home/julien/lib\" -DELIBDIR=\"\" -fno-strict-aliasing 
-Wall -g -02 -MT bloomfilter.lo -MD -MP -MF .deps/bloomfilter.Tpo -c 
bloomfilter.c -fPIC -DPIC -o .libs/bloomfilter.o
In file included from bloomfilter.c:42:
../../src/include/gnunet_util.h:69:18: ltdl.h: No such file or directory
make[3]: *** [bloomfilter.lo] Erreur 1
make[3]: Leaving directory 
`/home/julien/programmes/gnunet/GNUnet-0.6.1/src/util'
make[2]: *** [all-recursive] Erreur 1
make[2]: Leaving directory 
`/home/julien/programmes/gnunet/GNUnet-0.6.1/src/util'
make[1]: *** [all-recursive] Erreur 1
make[1]: Leaving directory `/home/julien/programmes/gnunet/GNUnet-0.6.1/src'
make : *** [all-recursive] Erreur 1

So I didn't succeed to install GNUnet.

My configuration is :
Mandrake 9.1 for i686
linux 2.4.21-0.13mdk
gcc 3.2.2
My home directory is /home/julien/

Thank you for your help.