[PATCH] add benchmark for strcoll

[Leonhard Holz]

Ok, I changed the code following to your proposals. But one doesnt work:

>
>> +  timing_t res __attribute__ ((unused));
>
> use __attribute_used__ instead

bench-strcoll.c: In function ‘do_bench’:
bench-strcoll.c:334:3: error: ‘__used__’ attribute ignored [-Werror=attributes]
    timing_t res __attribute_used__;
    ^