LWJGL does not provide libOpenCL.so, just like it doesn't provide an OpenGL implementation. OpenCL must be installed on your system separately, usually with your GPU drivers. You could also have multiple OpenCL platforms (e.g. the Intel OpenCL runtime with a CPU device and the Nvidia OpenCL implementation with a GPU device), in which case libOpenCL.so is the ICD loader (ICD = Installable Client Drivers) that can be used to choose one or the other (or both).