[dlopen] Undefined PLT symbol "xfile_new" (reloc type = 7, symnum = 43)

[William Pomian]

Hello,
I recently try to change my Makefile (hand made) in order to use automake 
and autoconf. So I naturaly have to use libtool.

My program opens a  plugin (.so)
This plugin uses fonctions located in the main program.
The problem is when I dlopen the plugin, it complains that it can't find 
some of theses functions symbols:
Undefined PLT symbol "xfile_new" (reloc type = 7, symnum = 43)

I have tried both dlopen with RTLD_NOW and DL_LAZY.
Nothing change expect the error message (There is "PLT" in one case).

When I creates the plugin, I compile it with 
LDFLAGS = -export-dynamic -module

$ nm my_program | grep xfile_new
08052204 T xfile_new

$ nm my_pluginl.so | grep xfile_new
                U xfile_new

Some idea to help my dlopen ?

Thx

William Pomian