[PATCH] Add return value to indicate unsopported cipher

[Sylvain Munaut]

Hi,

>> mmm, the "osmocom" usual way is to return 0 for success and a negative
>> error, in this case -ENOTSUP would be perfect.
>>
> Is there common place to define such error codes in osmocom?
>
> git grep -ni ENOTSUP
> reveals nothing of a kind.

Well we never used that one yet I guess, but those are defined in
errno.h part of POSIX AFAIK.

Cheers,

    Sylvain