Description: As the new OpenCL headers use 1.2 API and the nvidia libcl requires 1.1 version, OpenCL code does not
compile anymore

Additional info:
* opencl-headers 1:1.2.20130603-1
* libcl 1.1

When I try to compile my opencl code I get the following compilation error:

<code>
Linking CXX executable ../gen_system
CMakeFiles/gen_system.dir/lib/gen_system.cpp.o: In function `opencl::set_devices()':
gen_system.cpp:(.text+0x6cb8): undefined reference to `clReleaseDevice'
gen_system.cpp:(.text+0x6d00): undefined reference to `clReleaseDevice'
CMakeFiles/gen_system.dir/lib/gen_system.cpp.o: In function `opencl::~opencl()':
gen_system.cpp:(.text._ZN6openclD2Ev[_ZN6openclD5Ev]+0x80): undefined reference to `clReleaseDevice'
gen_system.cpp:(.text._ZN6openclD2Ev[_ZN6openclD5Ev]+0xc8): undefined reference to `clReleaseDevice'
CMakeFiles/gen_system.dir/lib/gen_system.cpp.o: In function `opencl::~opencl()':
gen_system.cpp:(.text._ZN6openclD0Ev[_ZN6openclD0Ev]+0x80): undefined reference to `clReleaseDevice'
CMakeFiles/gen_system.dir/lib/gen_system.cpp.o:gen_system.cpp:(.text._ZN6openclD0Ev[_ZN6openclD0Ev]+0xc8): more undefined references to `clReleaseDevice' follow
collect2: error: ld returned 1 exit status
make[2]: *** [../gen_system] Error 1
make[1]: *** [CMakeFiles/gen_system.dir/all] Error 2
make: *** [all] Error 2
</code>

The above error results from the API incompatibility between libcl and the new opencl-headers.