Dll linking using libtool

[lto]

I get the ***Warning from libtool when I try to link the library with 
another dll, using the import library cba.lib.
The cba.dll is in the same folder than the import library.
I don't understand why I get this warning, as invoking the wrapper from 
the command line with the same arguments
creates the desired library.
Any idea ?

Output from libtool is:
----------------------------------------------------------
mv -f RawBuffer.obj .libs/RawBuffer.lo
clwrapper -DPACKAGE=\"basic_services\" -DVERSION=\"1.0\" -DDEBUG=1 
"-DUSE_NAMESPACE=using namespace std" -DCBA=1 -I. -I. -I../includes 
-I../interfaces -IL:/packages/cba/interfaces -g -GX -D_WINDOWS -c 
RawBuffer.cpp >/dev/null 2>&1
mv -f .libs/RawBuffer.lo RawBuffer.lo
/bin/sh ../libtool --mode=link clwrapper  -g -GX -D_WINDOWS   
-LL:/packages/cba/win32-x86/lib/release/ -Wl,-g  -o libbasicservices.la 
-rpath /usr/local/lib -no-undefined -version-info 0:0:0 RawBuffer.lo 
L:/packages/cba/win32-x86/lib/release/cba.lib 
L:/packages/cba/win32-x86/lib/release/cba.dll 

*** Warning: This library needs some functionality provided by 
L:/packages/cba/win32-x86/lib/release/cba.lib.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have.
rm -fr .libs/libbasicservices.la .libs/libbasicservices.* 
.libs/libbasicservices.*
clwrapper -o .libs/libbasicservices-0.dll  RawBuffer.lo  -g `echo " 
-LL:/packages/cba/win32-x86/lib/release/" | sed -e 's/ -lc$//'` -link -dll
link phase is  /DEBUG:FULL /DEBUGTYPE:cv /DLL -subsystem:console 
/OUT:.libs\\libbasicservices-0.dll RawBuffer.lo  kernel32.lib user32.lib 
gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib uuid.lib 
comctl32.lib wsock32.lib winmm.lib
Microsoft (R) Incremental Linker Version 6.00.8447
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.

Creating library .libs\libbasicservices-0.lib and object 
.libs\libbasicservices-0.exp
RawBuffer.lo : error LNK2001: unresolved external symbol "public: 
virtual void __thiscall CBA_BaseClass::Delete(void)const " 
(address@hidden@@UBEXXZ)
RawBuffer.lo : error LNK2001: unresolved external symbol "public: 
virtual __thiscall CBA_BaseClass::~CBA_BaseClass(void)" 
(??1CBA_BaseClass@@address@hidden)
RawBuffer.lo : error LNK2001: unresolved external symbol "public: 
virtual __thiscall CBA_Exception::~CBA_Exception(void)" 
(??1CBA_Exception@@address@hidden)
RawBuffer.lo : error LNK2001: unresolved external symbol "public: 
__thiscall CBA_Exception::CBA_Exception(char const *,int)" 
(??0CBA_Exception@@address@hidden@Z)
.libs\libbasicservices-0.dll : fatal error LNK1120: 4 unresolved externals
make[1]: Leaving directory `/cygdrive/h/storage/BasicServices/src'
---------------------------------------------------------------------------------
The unresolved symbols come from the fact that the link line generated 
by libtool doesn't provide the cba library.

--
Loïc