sm: Support signing using ECDSA.
* sm/gpgsm.h (struct certlist_s): Add helper field pk_algo. * sm/sign.c (gpgsm_sign): Store the public key algo. Take the hash algo from the curve. Improve diagnostic output in verbose mode.
- GnuPG-bug-id: T4098
- Signed-off-by: Werner Koch <wk@gnupg.org>