By enabling a libclc extension on ethminer OpenCL code, I managed to run it using Ubuntu 16.04 and Oibaf's PPA. The code has been merged into https://github.com/ethereum/libethereum and you can benchmark it for yourself.

Using a Radeon r9 280X, I ran the following command:

$ ethminer -G -F mine.weipool.org:5555/0x7079a42c78d28ce9216c290d1bbc61e7b12d54a3/0.5

and got in output, among other things:

...
miner  01:09:13.001|ethminer  Mining on PoWhash #20c1b379… : 556569 H/s = 524288 hashes / 0.942 s
miner  01:09:13.875|ethminer  Mining on PoWhash #20c1b379… : 599871 H/s = 524288 hashes / 0.874 s
miner  01:09:14.758|ethminer  Mining on PoWhash #20c1b379… : 296878 H/s = 262144 hashes / 0.883 s
miner  01:09:15.624|ethminer  Mining on PoWhash #20c1b379… : 606113 H/s = 524288 hashes / 0.865 s
miner  01:09:16.480|ethminer  Mining on PoWhash #20c1b379… : 612485 H/s = 524288 hashes / 0.856 s
miner  01:09:17.353|ethminer  Mining on PoWhash #20c1b379… : 601247 H/s = 524288 hashes / 0.872 s
miner  01:09:18.210|ethminer  Mining on PoWhash #20c1b379… : 611771 H/s = 524288 hashes / 0.857 s
...

This reported rash rate is about 3% of the rate my GPU is supposed to deliver (it should be in the order of 22 MH/s). 

By the way, that command will mine on the public pool WeiPool and direct the earnings to my address 0x7079a42c78d28ce9216c290d1bbc61e7b12d54a3. If you want to try and don't send me money, change that number to you Ethereum or Bitcoin address. Instructions in mine.weipool.org.