[CMake] policy CMP0003 and full path, but still conflict with implicit directories

[PG]

Hi all,

I want to link a target to libraries A and B.
A is in the /usr/lib directory, and B is in another directory, say 
/some/path. My problem is that an old version of A also exists in the 
directory /some/path, and if I add this directory to the linker search 
path, /some/path/A will be found instead of /usr/lib/A.

I am using cmake 2.8 on linux (ubuntu 9.10 karmic), and found that with 
policy CMP0003, libraries with full path provided shouldn't produce 
linker search paths entry.
I made sure this policy is active by adding a
   CMAKE_POLICY(SET CMP0003 NEW)
even though I used
   CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
at the beginning of my CMakeList.txt file.

I add these to library to the linker using full path:
   TARGET_LINK_LIBRARY(target /usr/lib/A /some/path/B)

I run cmake and got the error:

CMake Warning at CMakeLists.txt:67 (add_executable):
   Cannot generate a safe linker search path for target target because files
   in some directories may conflict with libraries in implicit directories:

     link library [A] in /usr/lib may be hidden by files in:
       /some/path

   Some of these libraries may not be found correctly.


I checked the file CMakeFiles/target.dir/link.txt
and get a line like
   /usr/bin/c++ [...] -L/some/path -lA -lB
where I would like to see
   /usr/bin/c++ [...] -lA /some/path/B
according to what I understood from the CMP0003 policy help page.
This:
   /usr/bin/c++ [...] -lA -L/some/path/ -lB
would also work, but as far as I understand this is not what policy 
CMP0003 should produce.


I googled for a solution, but cannot find any that corresponds to my 
case. I still don't understand why I get the "-L" statement while using 
policy CMP0003.

I also tried adding a
   LINK_DIRECTORIES(/usr/include)
to get at least something like
   /usr/bin/c++ [...] -L/usr/lib,/some/path -lA -lB
so /usr/lib/A will be found prior to /some/path/A, but it didn't change 
anything. I guess it is because /usr/lib is an implicit directory.


Is there a way to have this working, knowing that B is from a third 
party software, meaning that I don't have control on what files are 
present or not in the /some/path directory?
I can of course manually edit the CMakeFiles/target.dir/link.txt file 
after running cmake, but as my code is to be installed by some users on 
their own computer, I would like to avoid asking them to do this.


Pierre