Arch Linux

Description:
Opencl and its all dependencies (optionals include) are installed but Darktable can not use Opencl libraries and after "darktable -d opencl" command;

"[xxx@yyy ~]$ darktable -d opencl
[opencl_init] opencl related configuration options:
[opencl_init]
[opencl_init] opencl: 1
[opencl_init] opencl_library: ''
[opencl_init] opencl_memory_requirement: 768
[opencl_init] opencl_memory_headroom: 300
[opencl_init] opencl_device_priority: '*/!0,*/*/*'
[opencl_init] opencl_size_roundup: 16
[opencl_init] opencl_async_pixelpipe: 0
[opencl_init] opencl_synch_cache: 0
[opencl_init] opencl_number_event_handles: 25
[opencl_init] opencl_micro_nap: 1000
[opencl_init] opencl_use_pinned_memory: 0
[opencl_init] opencl_use_cpu_devices: 0
[opencl_init] opencl_avoid_atomics: 0
[opencl_init] opencl_omit_whitebalance: 0
[opencl_init]
[opencl_init] trying to load opencl library: '<system default>'
[opencl_init] opencl library 'libOpenCL' found on your system and loaded
[opencl_init] could not get platforms: -1001
[opencl_init] FINALLY: opencl is NOT AVAILABLE on this system.
[opencl_init] initial status of opencl enabled flag is OFF.
Rawspeed, ISO:200, Estimated black:0, Estimated white: 16383
"

I use nvidia card and all nvidia packages for opencl are installed too.