plus d'opencl sous darktable

[patrick L]

j'ai remarqué y a quelques temps que la case "activer  le support d'opencl"  n'etait plus activée..   

j'ai lancé darktable-cltest et j'obtiens

Code :

$ darktable-cltest
[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_enable_markesteijn: 1
[opencl_init]
[opencl_init] could not find opencl runtime library 'libOpenCL'
[opencl_init] could not find opencl runtime library 'libOpenCL.so'
[opencl_init] found opencl runtime library 'libOpenCL.so.1'
[opencl_init] opencl library 'libOpenCL.so.1' 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.

j'ai les références de ma carte graphique.  
$ lspci -nn | grep VGA01:05.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] RS780L [Radeon 3000] [1002:9616]


$ lsb_release -a
LSB Version:    core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID:    LinuxMint
Description:    Linux Mint 18 Sarah
Release:    18
Codename:    sarah

je voudrais savoir si opencl  est bien installé  sur linux mint   et ensuite comment l'activer pour darktable. 

merci à tous de me permettre de faire tourner darktable plus rapidement (surtout avec le traitement du bruit).