kconfig: split list_head into a separate header

The struct list_head is often embedded in other structures, while other
code is used in C functions.

By separating struct list_head into its own header, other headers are no
longer required to include the entire list.h.

This is similar to the kernel space, where struct list_head is defined
in <linux/types.h> instead of <linux/list.h>.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/expr.h

@@ -12,7 +12,7 @@ extern "C" {
 
 #include <assert.h>
 #include <stdio.h>
-#include "list.h"
+#include "list_types.h"
 #ifndef __cplusplus
 #include <stdbool.h>
 #endif

scripts/kconfig/list.h

@@ -2,6 +2,8 @@
 #ifndef LIST_H
 #define LIST_H
 
+#include "list_types.h"
+
 /*
  * Copied from include/linux/...
  */
@@ -20,12 +22,6 @@
 	const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 	(type *)( (char *)__mptr - offsetof(type,member) );})
 
-
-struct list_head {
-	struct list_head *next, *prev;
-};
-
-
 #define LIST_HEAD_INIT(name) { &(name), &(name) }
 
 #define LIST_HEAD(name) \

scripts/kconfig/list_types.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LIST_TYPES_H
+#define LIST_TYPES_H
+
+struct list_head {
+	struct list_head *next, *prev;
+};
+
+#endif /* LIST_TYPES_H */

scripts/kconfig/mconf.c

@@ -19,6 +19,7 @@
 #include <signal.h>
 #include <unistd.h>
 
+#include "list.h"
 #include "lkc.h"
 #include "lxdialog/dialog.h"
 #include "mnconf-common.h"

scripts/kconfig/menu.c

@@ -10,6 +10,7 @@
 
 #include "lkc.h"
 #include "internal.h"
+#include "list.h"
 
 static const char nohelp_text[] = "There is no help available for this option.";
 

scripts/kconfig/nconf.c

@@ -11,6 +11,7 @@
 #include <strings.h>
 #include <stdlib.h>
 
+#include "list.h"
 #include "lkc.h"
 #include "mnconf-common.h"
 #include "nconf.h"