kbx: Fix for building without keyboxd.

* kbx/keybox-fwddecl.h: New.
* kbx/keybox.h: Replace typedef for KEYBOX_HANDLE by including the new
file.
* g10/keydb-private.h: Ditto.
--

The duplicated typedef was a bit ugly and will fail, depending on
compiler, iof for example building without keyboxd.  Fix only tested
in the standard case but the fix is obvious.

g10/keydb-private.h

@@ -23,13 +23,7 @@
 
 #include <assuan.h>
 #include "../common/membuf.h"
-
+#include "../kbx/keybox-fwddecl.h"
-
-/* Ugly forward declarations.  */
-struct keyring_handle;
-typedef struct keyring_handle *KEYRING_HANDLE;
-struct keybox_handle;
-typedef struct keybox_handle *KEYBOX_HANDLE;
 
 
 /* This is for keydb.c and only used in non-keyboxd mode. */

kbx/Makefile.am

@@ -44,7 +44,7 @@ common_libs = $(libcommon)
 commonpth_libs = $(libcommonpth)
 
 common_sources = \
-	keybox.h keybox-defs.h keybox-search-desc.h \
+	keybox.h keybox-defs.h keybox-search-desc.h keybox-fwddecl.h \
 	keybox-util.c \
 	keybox-init.c \
 	keybox-blob.c \

kbx/keybox-fwddecl.h

@@ -0,0 +1,30 @@
+/* keybox-fwddecl.h - Keybox specific forward declarations and definitions.
+ * Copyright (C) 2025 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#ifndef KEYBOX_FWDDECL_H
+#define KEYBOX_FWDDECL_H 1
+
+struct keyring_handle;
+typedef struct keyring_handle *KEYRING_HANDLE;
+
+struct keybox_handle;
+typedef struct keybox_handle *KEYBOX_HANDLE;
+
+#endif /*KEYBOX_FWDDECL_H*/

kbx/keybox.h

@@ -28,13 +28,12 @@ extern "C" {
 
 #include "../common/iobuf.h"
 #include "keybox-search-desc.h"
+#include "keybox-fwddecl.h"
 
 #ifdef KEYBOX_WITH_X509
 # include <ksba.h>
 #endif
 
-typedef struct keybox_handle *KEYBOX_HANDLE;
-
 
 typedef enum
   {