__malloc_lock

[Franzi Edo.]

Hi,
I am working on the porting of the reentrant version of newlib on my OS.
The problem I have is with __maloc_lock and __maloc_unlock  functions.
In a separate library I have written all the stubs (xyz_r) necessary  
to work (I put in this place my implementation of __malloc_lock and  
__malloc_unlock).
Now, when I link my application the linker indicate to me a multiple  
definition problem:

../../../../../../../../GCC/gcc-4.1.1/newlib/libc/stdlib/mlock.c:49:  
multiple definition of `__malloc_lock'

How can I  proceed to overwrite my __malloc_lock implementation over  
the standard one?

Cheers
   Edo