tree-wide: Introduce sd-forward.h and shared-forward.h headers

Let's not leak details from src/shared and src/libsystemd into
src/basic, even though you can't actually do anything useful with
just forward declarations from src/shared.

The sd-forward.h header is put in src/libsystemd/sd-common as we
don't have a directory for shared internal headers for libsystemd
yet.

Let's also rename forward.h to basic-forward.h to keep things
self-explanatory.

src/core/audit-fd.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int get_core_audit_fd(void);
 void close_core_audit_fd(void);

src/core/clock-warp.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int clock_reset_timewarp(void);
 void clock_apply_epoch(bool allow_backwards);

src/core/core-forward.h

@@ -2,7 +2,7 @@
 #pragma once
 
 #include "conf-parser-forward.h"        /* IWYU pragma: export */
-#include "forward.h"                    /* IWYU pragma: export */
+#include "shared-forward.h"             /* IWYU pragma: export */
 #include "unit-def.h"                   /* IWYU pragma: export */
 
 typedef enum CGroupDevicePermissions CGroupDevicePermissions;

src/core/crash-handler.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 typedef enum CrashAction {
         CRASH_FREEZE,

src/core/generator-setup.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "core-forward.h"
 
 int lookup_paths_mkdir_generator(LookupPaths *p);
 void lookup_paths_trim_generator(LookupPaths *p);

src/core/kill.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 typedef enum KillMode {
         /* The kill mode is a property of a unit. */

src/core/main.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 #include "crash-handler.h"
 
 extern bool arg_dump_core;

src/core/manager.h

@@ -6,7 +6,7 @@
 #include "cgroup.h"
 #include "common-signal.h"
 #include "execute.h"
-#include "forward.h"
+#include "shared-forward.h"
 #include "log.h"
 #include "path-lookup.h"
 #include "show-status.h"

src/core/namespace.h

@@ -5,7 +5,7 @@
   Copyright © 2016 Djalal Harouni
 ***/
 
-#include "forward.h"
+#include "core-forward.h"
 #include "list.h"
 #include "runtime-scope.h"
 

src/core/selinux-setup.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int mac_selinux_setup(bool *loaded_policy);

src/core/show-status.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 /* Manager status */
 

src/core/smack-setup.h

@@ -7,6 +7,6 @@
         Nathaniel Chen <nathaniel.chen@intel.com>
 ***/
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int mac_smack_setup(bool *loaded_policy);

src/core/unit-dependency-atom.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 /* Flags that identify the various "atomic" behaviours a specific dependency type implies. Each dependency is
  * a combination of one or more of these flags that define what they actually entail. */

src/core/varlink-cgroup.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int unit_cgroup_context_build_json(sd_json_variant **ret, const char *name, void *userdata);
 int unit_cgroup_runtime_build_json(sd_json_variant **ret, const char *name, void *userdata);

src/core/varlink-common.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int rlimit_build_json(sd_json_variant **ret, const char *name, void *userdata);
 int rlimit_table_build_json(sd_json_variant **ret, const char *name, void *userdata);

src/core/varlink-dynamic-user.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
 int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);

src/core/varlink-manager.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 int vl_method_describe_manager(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);

src/core/varlink-unit.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "forward.h"
+#include "shared-forward.h"
 
 #define VARLINK_ERROR_UNIT_NO_SUCH_UNIT "io.systemd.Unit.NoSuchUnit"