agent: Make "PKDECRYPT --kem" with optional value work.

* agent/command.c (cmd_pkdecrypt): Fix comparison.

* agent/agent.h (enum kemids): Rename type and strip trailing comma.

* agent/pkdecrypt.c (agent_hybrid_pgp_kem_decrypt): Allow building
with Libgcrypt < 1.11
--

Eventually we should change the libgcrypt requirement in configure.

agent/agent.h

@@ -560,11 +560,11 @@ gpg_error_t agent_pkdecrypt (ctrl_t ctrl, const char *desc_text,
                              const unsigned char *ciphertext, size_t ciphertextlen,
                              membuf_t *outbuf, int *r_padding);
 
-enum kemid
+enum kemids
   {
     KEM_PQC_PGP,
     KEM_PGP,
-    KEM_CMS,
+    KEM_CMS
   };
 
 gpg_error_t agent_kem_decrypt (ctrl_t ctrl, const char *desc_text, int kemid,

agent/command.c

@@ -1075,13 +1075,14 @@ cmd_pkdecrypt (assuan_context_t ctx, char *line)
   if (p)
     {
       kemid = KEM_PQC_PGP;
-      if (*p++ == '=')
+      if (*p == '=')
         {
-          if (strcmp (p, "PQC-PGP"))
+          p++;
+          if (!strcmp (p, "PQC-PGP"))
             kemid = KEM_PQC_PGP;
-          else if (strcmp (p, "PGP"))
+          else if (!strcmp (p, "PGP"))
             kemid = KEM_PGP;
-          else if (strcmp (p, "CMS"))
+          else if (!strcmp (p, "CMS"))
             kemid = KEM_CMS;
           else
             return set_error (GPG_ERR_ASS_PARAMETER, "invalid KEM algorithm");

agent/pkdecrypt.c

@@ -188,6 +188,7 @@ static gpg_error_t
 agent_hybrid_pgp_kem_decrypt (ctrl_t ctrl, const char *desc_text,
                               gcry_sexp_t s_cipher, membuf_t *outbuf)
 {
+#if GCRYPT_VERSION_NUMBER >= 0x010b00
   gcry_sexp_t s_skey0 = NULL;
   gcry_sexp_t s_skey1 = NULL;
   unsigned char *shadow_info = NULL;
@@ -408,6 +409,9 @@ agent_hybrid_pgp_kem_decrypt (ctrl_t ctrl, const char *desc_text,
   gcry_sexp_release (s_skey0);
   gcry_sexp_release (s_skey1);
   return err;
+#else
+  return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+#endif
 }
 
 /* DECRYPT the encrypted stuff (like encrypted session key) in