gpgsm: Support ECDSA in de-vs mode.

* common/compliance.h (PK_ALGO_FLAG_ECC18): New.
* common/compliance.c (gnupg_pk_is_allowed): Implement.
* sm/decrypt.c (gpgsm_decrypt): Pass new flag.
* sm/sign.c (gpgsm_sign): Ditto.
* sm/verify.c (gpgsm_verify): Ditto.
--

GnuPG-bug-id: 6802

common/compliance.h

@@ -50,6 +50,7 @@ enum pk_use_case
 
 /* Flags to distinguish public key algorithm variants.  */
 #define PK_ALGO_FLAG_RSAPSS 1    /* Use rsaPSS padding. */
+#define PK_ALGO_FLAG_ECC18  256  /* GCRY_PK_ECC is used in a generic way.  */
 
 
 int gnupg_pk_is_compliant (enum gnupg_compliance_mode compliance, int algo,