gpg: Autoload designated revoker key and ADSK when needed.

* g10/options.h (opt): Move the definition of struct akl to global
scope.
* g10/keydb.h (enum get_pubkey_modes): Add GET_PUBKEY_TRY_LDAP.
* g10/getkey.c (get_pubkey_byname): Implement GET_PUBKEY_BYNAME.
* g10/keygen.c (prepare_desig_revoker): Use it here.
(prepare_adsk): and here.
--

The revoker key is required before we create it along with a new key.
This is because the we need to know the algo and also to make sure
that the key really exists.

GnuPG-bug-id: 7133

g10/options.h

@@ -41,6 +41,26 @@ struct keyserver_spec
 };
 typedef struct keyserver_spec *keyserver_spec_t;
 
+/* The --auto-key-locate mechanisms object.  */
+struct akl
+{
+  enum {
+    AKL_NODEFAULT,
+    AKL_LOCAL,
+    AKL_CERT,
+    AKL_PKA,
+    AKL_DANE,
+    AKL_WKD,
+    AKL_LDAP,
+    AKL_NTDS,
+    AKL_KEYSERVER,
+    AKL_SPEC
+  } type;
+  keyserver_spec_t spec;
+  struct akl *next;
+};
+
+
 
 /* Global options for GPG.  */
 EXTERN_UNLESS_MAIN_MODULE
@@ -290,23 +310,7 @@ struct
 
   /* Linked list of ways to find a key if the key isn't on the local
      keyring. */
-  struct akl
-  {
-    enum {
-      AKL_NODEFAULT,
-      AKL_LOCAL,
-      AKL_CERT,
-      AKL_PKA,
-      AKL_DANE,
-      AKL_WKD,
-      AKL_LDAP,
-      AKL_NTDS,
-      AKL_KEYSERVER,
-      AKL_SPEC
-    } type;
-    keyserver_spec_t spec;
-    struct akl *next;
-  } *auto_key_locate;
+  struct akl *auto_key_locate;
 
   /* The value of --key-origin.  See parse_key_origin().  */
   int key_origin;
@@ -327,6 +331,7 @@ struct
   unsigned int compat_flags;
 } opt;
 
+
 /* CTRL is used to keep some global variables we currently can't
    avoid.  Future concurrent versions of gpg will put it into a per
    request structure CTRL. */