Add elliptic curve SM2 implementation.
* configure.ac (enabled_pubkey_ciphers): Add ecc-sm2. * cipher/Makefile.am (EXTRA_libcipher_la_SOURCES): Add ecc-sm2.c. * cipher/pubkey-util.c (_gcry_pk_util_parse_flaglist, _gcry_pk_util_preparse_sigval): Add sm2 flags. * cipher/ecc.c: Support ecc-sm2. * cipher/ecc-common.h: Add declarations for ecc-sm2. * cipher/ecc-sm2.c: New. * src/cipher.h: Define PUBKEY_FLAG_SM2.
- Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>